This file documents TRAMP 2.7.1, a remote file editing package for Emacs.
TRAMP stands for “Transparent Remote (file) Access, Multiple
Protocol”. This package provides an easy, convenient, and consistent
interface to editing remote files transparently, just as if they are
local files. This extends to editing, version control, dired
,
and more.
You can find the latest version of this document on the web at https://www.gnu.org/software/tramp/.
The latest release of TRAMP is available for download, or you may see Obtaining TRAMP for more details, including the Git server details.
TRAMP also has a Savannah Project Page.
There is a mailing list for TRAMP, available at tramp-devel@gnu.org, and archived at the TRAMP Mail Archive.
Copyright © 1999–2024 Free Software Foundation, Inc.
Permission is granted to copy, distribute and/or modify this document under the terms of the GNU Free Documentation License, Version 1.3 or any later version published by the Free Software Foundation; with no Invariant Sections, with the Front-Cover Texts being “A GNU Manual”, and with the Back-Cover Texts as in (a) below. A copy of the license is included in the section entitled “GNU Free Documentation License”.
(a) The FSF’s Back-Cover Text is: “You have the freedom to copy and modify this GNU manual.”
sudoedit
smbclient
shell
on a remote hostshell-command
on a remote hosteshell
on a remote hostTRAMP is for transparently accessing remote files from within
Emacs. TRAMP enables an easy, convenient, and consistent
interface to remote files as if they are local files. TRAMP’s
transparency extends to editing, version control, and dired
.
TRAMP can access remote hosts using any number of access
methods, such as ssh
, scp
, telnet
, and
related programs. If these programs can successfully pass
ASCII characters, TRAMP can use them. TRAMP
does not require or mandate 8-bit clean connections.
TRAMP’s most common access method is through ssh
, a
more secure alternative to ftp
and other older access
methods.
TRAMP on MS Windows operating systems is integrated with the
PuTTY package, and uses the plink
program.
TRAMP mostly operates transparently in the background using the connection programs. As long as these programs enable remote login and can use the terminal, TRAMP can adapt them for seamless and transparent access.
TRAMP temporarily transfers a remote file’s contents to the local host editing and related operations. TRAMP can also transfer files between hosts using standard Emacs interfaces, a benefit of direct integration of TRAMP in Emacs.
TRAMP can transfer files using any number of available host
programs for remote files, such as rcp
, scp
,
rsync
or (under MS Windows) pscp
. TRAMP
provides easy ways to specify these programs and customize them to
specific files, hosts, or access methods.
For faster small-size file transfers, TRAMP supports encoded
transfers directly through the shell using mimencode
or
uuencode
provided such tools are available on the remote
host.
Accessing a remote file through TRAMP entails a series of actions, many of which are transparent to the user. Yet some actions may require user response (such as entering passwords or completing file names). One typical scenario, opening a file on a remote host, is presented here to illustrate the steps involved:
C-x C-f to initiate find-file, enter part of the TRAMP file name, then hit TAB for completion. If this is the first time connecting to that host, here’s what happens:
telnet
, for
example) in the buffer. If on the other hand, the login name was
included in the file name portion, TRAMP sends the login name
followed by a newline.
ssh
or for telnet
). TRAMP displays the
password prompt in the minibuffer. TRAMP then sends whatever
is entered to the remote host, followed by a newline.
If TRAMP does not receive any messages within a timeout period (a minute, for example), then TRAMP responds with an error message about not finding the remote shell prompt. If there are any messages from the remote host, TRAMP displays them in the buffer.
For any ‘login failed’ message from the remote host, TRAMP aborts the login attempt, and repeats the login steps.
Note that for the remote shell, TRAMP invokes
/bin/sh
. The remote host must recognize ‘exec /bin/sh’
and execute the appropriate shell. This shell must support Bourne
shell syntax.
cd
and ls
commands to find
which files exist on the remote host. TRAMP sometimes uses
echo
with globbing. TRAMP checks if a file or
directory is writable with test
. After each command,
TRAMP parses the output from the remote host for completing
the next operation.
For inline transfers, TRAMP sends a command, such as ‘mimencode -b /path/to/remote/file’, waits until the output has accumulated in the buffer, then decodes that output to produce the file’s contents.
For external transfers, TRAMP sends a command as follows:
$ scp user@host:/path/to/remote/file <TMP>/tramp.4711
TRAMP reads the local temporary file <TMP>/tramp.4711 into a buffer, and then deletes the temporary file.1
I hope this has provided you with a basic overview of what happens behind the scenes when you open a file with TRAMP.
TRAMP is included as part of Emacs.
TRAMP is also freely packaged for download on the Internet at
https://ftp.gnu.org/gnu/tramp/. The version number of
TRAMP can be obtained by the variable tramp-version
.
For released TRAMP versions, this is a three-number string
like “2.4.5”.
A TRAMP release, which is packaged with Emacs, could differ slightly from the corresponding standalone release. This is because it isn’t always possible to synchronize release dates between Emacs and TRAMP. Such version numbers have the Emacs version number as suffix, like “2.4.5.27.2”. This means TRAMP 2.4.5 as integrated in Emacs 27.2. A complete list of TRAMP versions packaged with Emacs can be retrieved by
(assoc 'Tramp customize-package-emacs-version-alist)
TRAMP is also available as GNU ELPA package. Besides the standalone releases, further minor versions of TRAMP will appear on GNU ELPA, until the next TRAMP release appears. These minor versions have a four-number string, like “2.4.5.1”. The manual of the latest TRAMP ELPA package is located at https://elpa.gnu.org/packages/doc/tramp.html.
TRAMP development versions are available on Git servers. Development versions contain new and incomplete features. The development version of TRAMP is always the version number of the next release, plus the suffix “-pre”, like “2.4.4-pre”.
One way to obtain TRAMP from the Git server is to visit the Savannah project page at the following URL and then clicking on the Git link in the navigation bar at the top.
https://savannah.gnu.org/projects/tramp/
Another way is to follow the terminal session below:
$ cd ~/emacs $ git clone https://git.savannah.gnu.org/git/tramp.git
From behind a proxy:
$ git config --global http.proxy https://user:pwd@proxy.server.com:8080 $ git clone https://git.savannah.gnu.org/r/tramp.git
TRAMP developers:
$ git clone login@git.sv.gnu.org:/srv/git/tramp.git
After one of the above commands, ~/emacs/tramp will containing the latest version of TRAMP.
To fetch updates from the repository, use git pull
:
$ cd ~/emacs/tramp $ git pull
Run autoconf
as follows to generate an up-to-date
configure script:
$ cd ~/emacs/tramp $ autoconf
TRAMP is part of Emacs since version 22. If you use the version that comes with your Emacs, or the version from GNU ELPA, the following information is not necessary.
For installation, it requires at least the following program versions:
On MS Windows, you need Posix programs for installation. These and other useful Posix utilities can be obtained from one of several projects:
Installing TRAMP into your Emacs is a relatively easy process, at least compared to rebuilding your machine from scratch. ;)
Seriously, though, the installation should be a fairly simple matter. The easiest way to proceed is as follows:
$ ln -s tramp-2.7.1 tramp
cd
to ~/emacs/tramp/. If you’ve taken TRAMP
from the Git sources, type autoconf
in order to get an
up-to-date configure
script. This is needed only one time
after you’ve cloned TRAMP from Git.
./configure
to configure TRAMP for your system.
Running configure
takes a while. While running, it prints
some messages telling which features it is checking for.
make
to build the byte-compiled Lisp files as well as
the Info manual.
make install
to install the TRAMP Lisp files
and Info manual.
make clean
. To also remove
the files that configure
created, type make
distclean
instead.
make
command, don’t despair. You can still byte compile the *.el
files by opening Emacs in dired
(C-x d) mode, at
~/emacs/tramp/lisp. Mark the lisp files with m, then
press B to byte compile your selections.
Something similar can be done if there were problems creating the info manual. Just change to directory ~/emacs/tramp/texi and load the tramp.texi file in Emacs. Then press M-x texinfo-format-buffer RET to generate ~/emacs/tramp/info/tramp.
By default, make install
will install TRAMP’s files
in /usr/local/share/emacs/site-lisp and /usr/local/share/info. You can specify
an installation prefix other than /usr/local by giving
configure
the option --prefix=PATH. On GNU/Linux
systems, it has been reported useful to apply
$ ./configure --prefix=/usr
If your installed copy of Emacs is named something other than emacs, you will need to tell ‘make’ where to find it so that it can correctly byte-compile the TRAMP sources.
For example, to pass the Emacs command to be called:
$ ./configure --with-emacs=emacs27
If you specify the absolute path of the command, it must not contain
whitespaces. If you need it, the corresponding path shall be appended
to the PATH
environment variable.
Also, the --prefix=PATH option to configure
may not
be general enough to set the paths you want. If not, you can declare
the directories Lisp and Info files should be installed.
For example, to put the Lisp files in $HOME/elisp and the Info file in $HOME/info, you would type:
$ ./configure --with-lispdir=$HOME/elisp --infodir=$HOME/info
On MS Windows, given Emacs is installed at C:/Program Files/Emacs, you should apply
$ ./configure \ --with-lispdir='C:/Program Files/Emacs/share/emacs/site-lisp' \ --infodir='C:/Program Files/Emacs/share/info'
make
supports the DESTDIR
environment variable for staged
installation; See (standards)Command Variables:
$ make DESTDIR=/tmp install
Running configure
might result in errors or warnings. The
output explains in detail what’s going wrong.
In case of errors, it is mandatory to fix them before continuation.
This can be missing or wrong versions of emacs
, Emacs
packages, make
, or makeinfo
.
Warnings let configure
(and the whole installation process)
continue, but parts of TRAMP aren’t installed. This can
happen with missing or wrong versions of texi2dvi
or
install-info
. Here you can decide yourself whether you want
to renounce on the related feature (tramp.dvi file for printed
output, TRAMP entry in Info’s dir file), or whether you
want to adapt your PATH
environment variable, and rerun
configure
. An alternative is calling the missed parts
manually later on.
TRAMP comes with compatibility code for different Emacs versions. When you upgrade your Emacs major version, it is necessary to recompile at least the TRAMP Lisp files. You must apply the following steps:
$ ./configure --with-emacs=emacs27
$ make -C lisp distclean all
$ make install
If you have installed TRAMP as GNU ELPA package, you can recompile it with the Emacs version you are running by the command M-x tramp-recompile-elpa RET.
TRAMP comes with an own test suite. In order to run this test suite, you call
$ make check
This test suite uses a mock-up connection method for the tests. This
means, that no real connection is established, and no password is
required for the tests. You can change this default behaviour by
tweaking the environment variable REMOTE_TEMPORARY_FILE_DIRECTORY
:
$ env REMOTE_TEMPORARY_FILE_DIRECTORY=/sudo::/tmp make check
If you are using MS Windows, the mock-up trick does not work, and you must change the default anyway.
See the file test/README for further details how to run the test suite.
If there are errors in that test suite you could not cover yourself, you might send a bug report.
If you don’t install TRAMP into the intended directories, but prefer to use from the source directory, you need to add the following lines into your .emacs:
(add-to-list 'load-path "~/emacs/tramp/lisp/") (require 'tramp)
If the environment variable INFOPATH
is set, add the directory
~/emacs/tramp/info/ to it. Else, add the directory to
Info-directory-list
, as follows:
(add-to-list 'Info-directory-list "~/emacs/tramp/info/")
TRAMP must be compiled for the Emacs version you are running. If you experience compatibility error messages for the TRAMP package, or if you use another major Emacs version than the version TRAMP has been installed with, you must recompile the package:
M-x package-recompile RET tramp
$ rm -f ~/.emacs.d/elpa/tramp-2.7.1/tramp*.elc
$ emacs -L ~/.emacs.d/elpa/tramp-2.7.1 -l tramp
This should not give you the error.
M-x tramp-recompile-elpa
Afterwards, you must restart Emacs.
Due to a bug in Emacs 29.1, you must apply the following change prior installation or upgrading TRAMP 2.7.1 from GNU ELPA:
(when (string-equal emacs-version "29.1") (with-current-buffer (url-retrieve-synchronously "https://git.savannah.gnu.org/cgit/emacs.git/plain/lisp/emacs-lisp/loaddefs-gen.el?h=emacs-29") (goto-char (point-min)) (while (looking-at "^.+$") (forward-line)) (eval-region (point) (point-max))))
TRAMP extends the Emacs file name syntax by adding a remote component. A remote file name always looks like /method:user@host:/path/to/file.
You can use remote files exactly like ordinary files, that means you
can open a file or directory by C-x C-f
/method:user@host:/path/to/file RET, edit the file,
and save it. You can also mix local files and remote files in file
operations with two arguments, like copy-file
or
rename-file
. And finally, you can even run processes on a
remote host, when the buffer you call the process from has a remote
default-directory
.
sudoedit
smbclient
Remote file names have method
, user
and host
parts prepended. All of them, and also the local file name part, are
optional, in case of a missing part a default value is assumed. The
default value for an empty local file name part is the remote user’s
home directory. The shortest remote file name is thus
/-::. The ‘-’ notation for the default method is
used for syntactical reasons, see Selecting a default method.
The method
part describes the connection method used to reach
the remote host, see below.
The user
part is the user name for accessing the remote host.
For the smb method, this could also require a domain name, in
which case it is written as user%domain
.
The host
part must be a host name which can be resolved on
your local host. It could be a short host name, a fully qualified
domain name, an IPv4 or IPv6 address, see TRAMP file name conventions. Some
connection methods also support a notation for the port to be used, in
which case it is written as host#port
.
If your local host runs an SSH client, and the remote host runs an SSH server, the simplest remote file name is /ssh:user@host:/path/to/file. The remote file name /ssh:: opens a remote connection to yourself on the local host, and is often used for testing TRAMP.
On MS Windows, PuTTY is often used as the SSH client. Its plink
method can be used there to open a connection to a remote host running
an ssh
server:
/plink:user@host:/path/to/file.
Sometimes, it is necessary to work on your local host under different
permissions. For this, you can use the su or sudo
connection method. If your system is systemd
-based, there is
the run0 connection method. On OpenBSD systems, the
doas connection method offers the same functionality. If
your local system is Android, use the method androidsu
instead of su.
These methods use ‘root’ as default user name and the return
value of (system-name)
as default host name. Therefore, it is
convenient to open a file as /sudo::/path/to/file.
The method sg stands for “switch group”; here the user name is used as the group to change to. The default host name is the same.
If the su, sudo, doas or run0 method should be performed on another host, it can be combined with a leading ssh or plink method. That means that TRAMP connects first to the other host with non-administrative credentials, and changes to administrative credentials on that host afterwards. In a simple case, the syntax looks like /ssh:user@host|sudo::/path/to/file. See Declaring multiple hops in the file name.
sudoedit
¶The sudoedit method is similar to the sudo method. However, it is a different implementation: it does not keep an open session running in the background. This is for security reasons; on the backside this method has worse performance than the sudo method, it is restricted to ‘localhost’ only, and it does not support external processes.
smbclient
¶In order to access a remote MS Windows host or Samba server, the
smbclient
client is used. The remote file name syntax is
/smb:user%domain@host:/path/to/file. The first part
of the local file name is the share exported by the remote host,
‘path’ in this example.
On systems which have GVFS (the GNOME Virtual File System) installed, its offered methods can be used by TRAMP. Examples are /sftp:user@host:/path/to/file, /afp:user@host:/path/to/file (accessing Apple’s AFP file system), /dav:user@host:/path/to/file, /davs:user@host:/path/to/file (for WebDAV shares) and /mtp:device:/path/to/file (for media devices).
GVFS-based methods also include GNOME Online Accounts, which support the Files service. These are the Google Drive file system, and the OwnCloud/NextCloud file system. The file name syntax here is always /gdrive:john.doe@gmail.com:/path/to/file (‘john.doe@gmail.com’ stands here for your Google Drive account), or /nextcloud:user@host#8081:/path/to/file (‘8081’ stands for the port number) for OwnCloud/NextCloud files.
FUSE (Filesystem in Userspace) allows users to mount a virtual file system. It is also used by GVFS internally, but here we discuss methods which do not use the GVFS API.
A convenient way to access system storages is the rclone
program. If you have configured a storage in rclone
under a
name ‘storage’ (for example), you can access it via the remote
file name syntax /rclone:storage:/path/to/file. User
names are not needed.
On local hosts which have installed the sshfs
client for
mounting a file system based on sftp
, this method can be
used. All remote files are available via the local mount point.
TRAMP aids in mounting the file system if it isn’t mounted
yet, and it supports the access with the usual file name syntax
/sshfs:user@host:/path/to/file.
An Android device, which is connected via USB to your local host, can
be accessed via the adb
command. No user or host name is
needed. The file name syntax is /adb::/path/to/file.
TRAMP is initially configured to use the scp
program
to connect to the remote host. Just type C-x C-f and then enter
file name /scp:user@host:/path/to/file. For details,
See Selecting a default method, See Selecting a default user, See Selecting a default host.
For problems related to the behavior of the remote shell, See Remote shell setup hints.
For changing the connection type and file access method from the defaults to one of several other options, See Types of connections to remote hosts.
Note that some user options described in these examples are not auto loaded by Emacs. All examples require TRAMP to be installed and loaded:
(customize-set-variable 'tramp-verbose 6 "Enable remote command traces")
For functions used to configure TRAMP, the following clause may be used in your init file:
(with-eval-after-load 'tramp (tramp-change-syntax 'simplified))
Changing other variables via directory-local variables on a remote
directory must be enabled by setting enable-remote-dir-locals
to non-nil
, See (emacs)Directory Variables.
Not all methods are enabled by default after loading TRAMP. Some of them don’t work on the local host. Some of them are optional, and must be enabled if it is intended to use them. For all methods described in this manual, it is indicated when the method is optional.
This command enables the optional method method, a string. The command can be invoked interactively like M-x tramp-enable-method RET toolbox RET, with toolbox being an optional method.
If you want to enable an optional method permanently, add something like this to your .emacs file:
(with-eval-after-load 'tramp (tramp-enable-method "toolbox"))
Inline method and external method are the two basic types
of access methods. While they both use the same remote shell access
programs, such as rsh
, ssh
, or telnet
,
they differ in the file access methods. Choosing the right method
becomes important for editing files, transferring large files, or
operating on a large number of files.
The performance of the external methods is generally better than that of the inline methods, at least for large files. This is caused by the need to encode and decode the data when transferring inline.
The one exception to this rule are the scp-based access methods. While these methods do see better performance when actually transferring files, the overhead of the cryptographic negotiation at startup may drown out the improvement in file transfer times.
External methods should be configured in such a way that they don’t
require a password (with ssh-agent
, or similar). Modern
scp
implementations offer options to reuse existing
ssh
connections, which TRAMP enables by default if
available. If that is not possible, you should consider Reusing passwords for several connections, otherwise you will be prompted for a password for every
copy action.
Inline methods use the same login connection to transfer file contents. Inline methods are quick and easy for small files. They depend on the availability of suitable encoding and decoding programs on the remote host. For local source and destination, TRAMP may use built-in equivalents of such programs in Emacs.
Inline methods can work in situations where an external transfer program is unavailable. Inline methods also work when transferring files between different user identities on the same host.
TRAMP checks the remote host for the availability and
usability of one of the commands defined in
tramp-remote-coding-commands
. TRAMP uses the first
reliable command it finds. TRAMP’s search path can be
customized, see How TRAMP finds and uses programs on the remote host.
In case none of the commands are available, TRAMP first transfers a small Perl program to the remote host, and then tries to use that program for encoding and decoding.
To increase transfer speeds for large text files, TRAMP can
use compression before encoding. The user option
tramp-inline-compress-start-size
specifies the file size above
which to use this optimization. This feature depends on the
availability and usability of one of the commands defined in
tramp-inline-compress-commands
.
rsh
is an option for connecting to hosts within local
networks since rsh
is not as secure as other methods.
There should be no reason to use it, as ssh
is a both a
complete replacement and ubiquitous.
ssh
is a more secure option than others to connect to a
remote host.
ssh
can also take extra parameters as port numbers. For
example, a host on port 42 is specified as host#42 (the real
host name, a hash sign, then a port number). It is the same as passing
‘-p 42’ to the ssh
command.
Connecting to a remote host with telnet
is as insecure
as the rsh method.
Instead of connecting to a remote host, su
program allows
editing as another user. The host can be either ‘localhost’ or
the host returned by the function (system-name)
. See
Connecting to a remote host using multiple hops for an exception to this behavior.
Because the default implementation of the su method and other
shell-based methods conflict with non-standard su
implementations popular among Android users and the restricted
command-line utilities distributed with that system, a largely
equivalent androidsu method is provided for that system with
workarounds for its many idiosyncrasies, with the exception that
multi-hops are unsupported.
This is an optional method, see Optional methods which must be enabled first. It is enabled by
default on android
systems only.
Similar to su method, sudo uses sudo
.
sudo
must have sufficient rights to start a shell.
For security reasons, a sudo connection is disabled after a predefined timeout (5 minutes by default). This can be changed, see Setting own connection related information.
This method is used on OpenBSD like the sudo
command. Like
the sudo method, a doas connection is disabled after
a predefined timeout.
This method is used on systemd
-based hosts. Internally, it
uses the systemd-run
command. A run0 connection is
disabled after a predefined timeout as well.
This is an optional method, see Optional methods which must be enabled first.
The sg
program allows editing as different group. The host
can be either ‘localhost’ or the host returned by the function
(system-name)
. The user name must be specified, but it
denotes a group name. See Connecting to a remote host using multiple hops for an exception to this
behavior.
Works like ssh but without the extra authentication prompts.
sshx uses ‘ssh -t -t -l user -o
RemoteCommand='/bin/sh -i' host’ to open a connection with a
“standard” login shell. It supports changing the remote login shell
/bin/sh
.
Note that sshx does not bypass authentication questions. For example, if the host key of the remote host is not known, sshx will still ask “Are you sure you want to continue connecting?”. TRAMP cannot handle such questions. Connections will have to be setup where logins can proceed without such questions.
sshx is useful for MS Windows users when ssh
triggers an error about allocating a pseudo tty. This happens due to
missing shell prompts that confuses TRAMP.
sshx supports the ‘-p’ argument.
This method is also similar to ssh. It uses the
krlogin -x
command only for remote host login.
This method is an optional method, see Optional methods which must be enabled first.
This is another method from the Kerberos suite. It behaves like su. It is an optional method, see Optional methods which must be enabled first.
plink method is for MS Windows users with the PuTTY
implementation of SSH. It uses ‘plink -ssh’ to log in to the
remote host. It supports changing the remote login shell /bin/sh
.
Check the ‘Share SSH connections if possible’ control for that session.
plink method supports the ‘-P’ argument.
Another method using PuTTY on MS Windows with session names instead of
host names. plinkx calls ‘plink -load session
-t’. User names and port numbers must be defined in the session. It
supports changing the remote login shell /bin/sh
.
Check the ‘Share SSH connections if possible’ control for that session.
The following methods allow to access running containers in different ways:
Integration for Docker containers. The host name may be either a running container’s name or ID, as returned by ‘docker ps’.
Podman is an alternative to docker which may be run rootless, if desired.
Integration for containers in Kubernetes pods. The host name is ‘pod’, or ‘container.pod’ if an explicit container name shall be used. Otherwise, the first container in a pod is used.
This method does not support user names.
Integration of Toolbox or Distrobox system containers, respectively. The host name may be either a container’s name or ID, as returned by ‘toolbox list -c’ or ‘distrobox list’. Without a host name, the default Toolbox container for the host will be used. There is no such default for Distrobox.
Contrary to the other container-based methods, these two methods start a created container, if it isn’t running yet.
These are optional methods, see Optional methods which must be enabled first. They do not support user names.
Integration of Flatpak sandboxes. The host name may be either an application ID, a sandbox instance ID, or a PID, as returned by ‘flatpak ps’.
This is an optional method, see Optional methods which must be enabled first. It does not support user names.
Integration of Apptainer instances. The host name is the instance name, as returned by ‘apptainer instance list’.
This is an optional method, see Optional methods which must be enabled first. It does not support user names.
Integration of systemd-nspawn
instances. The host name is the
instance name, as returned by ‘machinectl list --all’.
This is an optional method, see Optional methods which must be enabled first.
External methods operate over multiple channels, using the remote shell connection for some actions while delegating file transfers to an external transfer program.
External methods save on the overhead of encoding and decoding of inline methods.
Since external methods have the overhead of opening a new channel,
files smaller than tramp-copy-size-limit
still use inline
methods.
This method uses the rsh
and rcp
commands to
connect to the remote host and transfer files. This is the fastest
access method available.
The alternative method remcp uses the remsh
and
rcp
commands.
Using a combination of ssh
to connect and scp
to
transfer is the most secure. While the performance is good, it is
slower than the inline methods for smaller files. Though there is no
overhead of encoding and decoding of the inline methods,
scp
’s cryptographic handshake negates those speed gains.
ssh-based methods support ‘-p’ feature for specifying
port numbers. For example, host#42 passes ‘-p 42’ in the
argument list to ssh
, and ‘-P 42’ in the argument list
to scp
.
ssh
command to connect in combination with rsync
command to transfer is similar to the scp method.
rsync
performs much better than scp
when
transferring files that exist on both hosts. However, this advantage
is lost if the file exists only on one side of the connection.
This method supports the ‘-p’ argument.
scpx is useful to avoid login shell questions. It is similar
in performance to scp. scpx uses ‘ssh -t -t -l
user -o RemoteCommand='/bin/sh -i' host’ to open a
connection. It supports changing the remote login shell
/bin/sh
.
scpx is useful for MS Windows users when ssh
triggers an error about allocating a pseudo tty. This happens due to
missing shell prompts that confuses TRAMP.
This method supports the ‘-p’ argument.
These methods are similar to scp or sftp, but they
use the plink
command to connect to the remote host, and
they use pscp
or psftp
for transferring the files.
These programs are part of PuTTY, an SSH implementation for MS Windows.
They support changing the remote login shell /bin/sh
.
Check the ‘Share SSH connections if possible’ control for that session.
These methods support the ‘-P’ argument.
These methods are similar to docker or podman, but
they use the command docker cp
or podman cp
for
transferring large files.
These copy commands do not support file globs, and they ignore a user name.
This method is similar to scp, but uses fsh
to
connect and fcp
to transfer files. fsh/fcp
, a
front-end for ssh
, reuse ssh
session by
submitting several commands. This avoids the startup overhead due to
scp
’s secure connection. Inline methods have similar
benefits.
The command used for this connection is: ‘fsh host -l user /bin/sh -i’
fsh has no inline method since the multiplexing it offers is
not useful for TRAMP. fsh
connects to remote host
and TRAMP keeps that one connection open.
This is an optional method, see Optional methods which must be enabled first.
Using telnet
to connect and nc
to transfer files
is sometimes the only combination suitable for accessing routers or
NAS hosts. These dumb devices have severely restricted local shells,
such as the busybox
and do not host any other encode or
decode programs.
This is an optional method, see Optional methods which must be enabled first.
The sudoedit method facilitates editing a file as a different
user on the local host. You could regard this as TRAMP’s
implementation of the sudoedit
. Contrary to the
sudo method, all magic file name functions are implemented by
single sudo …
commands. The purpose is to make
editing such a file as secure as possible; there must be no session
running in the Emacs background which could be attacked from inside
Emacs.
Consequently, external processes are not implemented.
The host name of such remote file names must represent the local host. Since the default value is already proper, it is recommended not to use any host name in the remote file name, like /sudoedit::/path/to/file or /sudoedit:user@:/path/to/file.
Like the sudo method, a sudoedit password expires after a predefined timeout.
When TRAMP uses ftp, it forwards requests to whatever ftp program is specified by Ange FTP. This external program must be capable of servicing requests from TRAMP.
This non-native TRAMP method connects via the Server Message Block (SMB) networking protocol to hosts running file servers that are typically based on Samba or MS Windows.
Using smbclient
requires a few tweaks when working with
TRAMP:
The first directory in the localname must be a share name on the remote host.
Since some SMB share names end in the $
character,
TRAMP must use $$
when specifying those shares to avoid
environment variable substitutions.
When TRAMP is not specific about the share name or uses the
generic remote directory /, smbclient
returns all
available shares.
Since SMB authentication is based on each SMB share, TRAMP prompts for a password even when accessing a different share on the same SMB host. This prompting can be suppressed by Reusing passwords for several connections.
To accommodate user name/domain name syntax required by MS Windows
authorization, TRAMP provides for an extended syntax in
user%domain
format (where user
is the user name,
%
is the percent symbol, and domain
is the MS Windows
domain name). An example:
/smb:daniel%BIZARRE@melancholia:/daniel$$/.emacs
where user ‘daniel’ connects as a domain user to the SMB host ‘melancholia’ in the MS Windows domain ‘BIZARRE’ to edit .emacs located in the home directory (share ‘daniel$’).
Alternatively, for local WINS users (as opposed to domain users), substitute the domain name with the name of the local host in UPPERCASE as shown here:
/smb:daniel%MELANCHOLIA@melancholia:/daniel$$/.emacs
where user ‘daniel’ connects as local user to the SMB host ‘melancholia’ in the local domain ‘MELANCHOLIA’ to edit .emacs located in the home directory (share ‘daniel$’).
The domain name and user name are optional for smbclient
authentication. When user name is not specified, smbclient
uses the anonymous user (without prompting for password). This
behavior is unlike other TRAMP methods, where local user name
is substituted.
The smb method is unavailable if Emacs is run under a local user authentication context in MS Windows. However such users can still access remote files using UNC file names instead of TRAMP:
//melancholia/daniel$$/.emacs
UNC file name specification does not allow the specification of a
different user name for authentication like the smbclient
can.
This method uses Android Debug Bridge program for accessing Android
devices. The Android Debug Bridge must be installed locally for
TRAMP to work. Some GNU/Linux distributions provide Android
Debug Bridge as an installation package. Alternatively, the program
is installed as part of the Android SDK. TRAMP finds the
adb
program either via the PATH
environment variable
or the absolute path set in the user option tramp-adb-program
.
TRAMP connects to Android devices with adb only when
the user option tramp-adb-connect-if-not-connected
is not
nil
. Otherwise, the connection must be established outside
Emacs.
TRAMP does not require a host name part of the remote file
name when a single Android device is connected to adb
.
TRAMP instead uses /adb:: as the default name.
adb devices
, run in a shell outside Emacs, shows available
host names.
adb method normally does not need user name to authenticate
on the Android device because it runs under the adbd
process. But when a user name is specified, however, TRAMP
applies an su
in the syntax. When authentication does not
succeed, especially on un-rooted Android devices, TRAMP
displays login errors.
For Android devices connected through TCP/IP, a port number can be
specified using device#42 host name syntax or TRAMP can
use the default value as declared in adb
command. Port
numbers are not applicable to Android devices connected through USB.
GVFS is the virtual file system for the GNOME Desktop, https://en.wikipedia.org/wiki/GVFS. Remote files on GVFS are mounted locally through FUSE and TRAMP uses this locally mounted directory internally.
Emacs uses the D-Bus mechanism to communicate with GVFS. Emacs must have the message bus system, D-Bus integration active, see D-Bus.
This method is for connecting to remote hosts with the Apple Filing Protocol for accessing files on macOS volumes. TRAMP access syntax requires a leading volume (share) name, for example: /afp:user@host:/volume.
dav method provides access to WebDAV files and directories based on standard protocols, such as HTTP. davs does the same but with SSL encryption. Both methods support the port numbers.
Paths being part of the WebDAV volume to be mounted by GVFS, as it is common for OwnCloud or NextCloud file names, are not supported by these methods. See method nextcloud for handling them.
Via the gdrive method it is possible to access your Google
Drive online storage. User and host name of the remote file name are
your email address of the Google Drive credentials, like
/gdrive:john.doe@gmail.com:/. These credentials must
be populated in your Online Accounts
application outside Emacs.
Since Google Drive uses cryptic blob file names internally,
TRAMP works with the display-name
of the files. This
could produce unexpected behavior in case two files in the same
directory have the same display-name
, such a situation must be
avoided.
Media devices, like cell phones, tablets, cameras, can be accessed via the mtp method. Just the device name is needed in order to specify the host in the file name. However, the device must already be connected via USB, before accessing it. Possible device names are visible via host name completion, see File name completion.
Depending on the device type, the access could be read-only. Some devices are accessible under different names in parallel, offering different parts of their file system.
TRAMP does not require a host name as part of the remote file name when a single media device is connected. TRAMP instead uses /mtp:: as the default name.
As the name indicates, the method nextcloud allows you to
access OwnCloud or NextCloud hosted files and directories. Like the
gdrive method, your credentials must be populated in your
Online Accounts
application outside Emacs. The method
supports port numbers.
This method uses sftp
in order to securely access remote
hosts. sftp
is a more secure option for connecting to hosts
that for security reasons refuse ssh
connections.
When there is a respective entry in your ssh
configuration,
do not set the RemoteCommand option.
This user option is a list of external methods for GVFS. By default, this list includes afp, dav, davs, gdrive, mtp, nextcloud and sftp. Other methods to include are ftp, http, https and smb. These methods are not intended to be used directly as GVFS-based method. Instead, they are added here for the benefit of Archive file names.
If you want to use GVFS-based ftp or smb
methods, you must add them to tramp-gvfs-methods
, and you must
disable the corresponding TRAMP package by setting
tramp-ftp-method
or tramp-smb-method
to nil
,
respectively:
(add-to-list 'tramp-gvfs-methods "ftp") (customize-set-variable 'tramp-ftp-method nil)
Besides GVFS, there are other virtual file systems using the FUSE interface. Remote files are mounted locally through FUSE and TRAMP uses this locally mounted directory internally. When possible, TRAMP maps the remote file names to their respective local file name, and applies the file name operation on them. For some of the file name operations this is not possible, TRAMP emulates those operations otherwise.
The program rclone
enables accessing different system
storages in the cloud, see https://rclone.org/ for a list of
supported systems. If the rclone
program isn’t found in
your PATH
environment variable, you can tell TRAMP its
absolute path via the user option tramp-rclone-program
.
A system storage must be configured via the rclone config
command, outside Emacs. If you have configured a storage in
rclone
under a name ‘storage’ (for example), you could
access it via the remote file name
/rclone:storage:/path/to/file
User names are part of the rclone
configuration, and not
needed in the remote file name. If a user name is contained in the
remote file name, it is ignored.
Access via rclone is slow. If you have an alternative method for accessing the system storage, you should use it. GVFS-based external methods for example, methods gdrive and nextcloud.
On local hosts which have installed the sshfs
client for
mounting a file system based on sftp
, this method can be
used, see
https://github.com/libfuse/sshfs/blob/master/README.rst/. If
the sshfs
program isn’t found in your PATH
environment
variable, you can tell TRAMP its absolute path via the user
option tramp-sshfs-program
.
All remote files are available via the local mount point. TRAMP aids in mounting the file system if it isn’t mounted yet. The remote file name syntax is
/sshfs:user@host#port:/path/to/file
User name and port number are optional. This method does not support password handling, the file system must either be mounted already, or the connection must be established passwordless via ssh keys.
The mount point and mount arguments could be passed as connection properties, See Setup of sshfs method.
In a remote file name, the use of a default method is indicated by the pseudo method -, see TRAMP file name conventions.
Default method is for transferring files. The user option
tramp-default-method
sets it. TRAMP uses this user
option to determine the default method for remote file names that do
not have one specified.
(customize-set-variable 'tramp-default-method "ssh")
Default methods for transferring files can be customized for specific
user and host combinations through the user option
tramp-default-method-alist
.
For example, the following two lines specify to use the ssh method for all user names matching ‘john’ and the rsync method for all host names matching ‘lily’. The third line specifies to use the su method for the user ‘root’ on the host ‘localhost’.
(add-to-list 'tramp-default-method-alist '("" "john" "ssh")) (add-to-list 'tramp-default-method-alist '("lily" "" "rsync")) (add-to-list 'tramp-default-method-alist '("\\`localhost\\'" "\\`root\\'" "su"))
External methods performance faster for large files. see Inline methods. see External methods.
Choosing the access method also depends on the security environment. For example, rsh and telnet methods that use clear text password transfers are inappropriate for over the Internet connections. Secure remote connections should use ssh that provide encryption.
TRAMP provides maximum number of choices for maximum flexibility. Choosing which method depends on the hosts, clients, network speeds, and the security context.
Start by using an inline method.
External methods might be more efficient for large files, but most TRAMP users edit small files more often than large files.
Enable compression, tramp-inline-compress-start-size
, for a
performance boost for large files with inline methods.
Since ssh
has become the most common method of remote host
access and it has the most reasonable security protocols, use
ssh method. Typical ssh usage to edit the
/etc/motd file on the otherhost:
C-x C-f /ssh:root@otherhost:/etc/motd RET
If ssh is unavailable for whatever reason, look for other obvious options. For MS Windows, try the plink method2. For Kerberos, try krlogin.
For editing local files as su or sudo methods, try the shortened syntax of ‘root’:
C-x C-f /su::/etc/motd RET
For editing large files, scp is faster than ssh. pscp is faster than plink. But this speed improvement is not always true.
When copying large files between two different remote hosts via
scp, set tramp-use-scp-direct-remote-copying
to
non-nil
.
A TRAMP file name can omit the user name part since
TRAMP substitutes the currently logged-in user name. However
this substitution can be overridden with tramp-default-user
.
For example:
(customize-set-variable 'tramp-default-user "root")
Instead of a single default user, tramp-default-user-alist
allows multiple default user values based on access method or host
name combinations. The alist can hold multiple values. For example, to
use the ‘john’ as the default user for the domain
‘somewhere.else’ only:
(add-to-list 'tramp-default-user-alist '("ssh" ".*\\.somewhere\\.else\\'" "john"))
A Caution: TRAMP will override any default user specified in
the configuration files outside Emacs, such as ~/.ssh/config.
To stop TRAMP from applying the default value, set the
corresponding alist entry to nil
:
(add-to-list 'tramp-default-user-alist '("ssh" "\\`here\\.somewhere\\.else\\'" nil))
The last entry in tramp-default-user-alist
should be reserved
for catch-all or most often used login.
(add-to-list 'tramp-default-user-alist '(nil nil "jonas") t)
When host name is omitted, TRAMP substitutes the value from
the tramp-default-host
user option. It is initially
populated with the local host name where Emacs is running. The
default method, default user and default host can be overridden as
follows:
(custom-set-variables '(tramp-default-method "ssh") '(tramp-default-user "john") '(tramp-default-host "target"))
With all defaults set, /-:: will connect TRAMP to John’s home directory on ‘target’ via method ssh.
Instead of a single default host, tramp-default-host-alist
allows multiple default host values based on access method or user
name combinations. The alist can hold multiple values. While
tramp-default-host
is sufficient in most cases, some methods,
like adb, require defaults overwritten.
The default host name for nspawn is ‘.host’. Therefore, /nspawn:: and /sudo:: have the same effect.
Multi-hops are methods to reach hosts behind firewalls or to reach the outside world from inside a bastion host. With multi-hops, TRAMP can negotiate these hops with the appropriate user/host authentication at each hop. All methods until now have been the single hop kind, where the start and end points of the connection did not have intermediate check points.
tramp-default-proxies-alist
specifies proxy hosts to pass
through. This user option is list of triples consisting of
(host user proxy)
.
The first match is the proxy host through which passes the file name
and the target host matching user@host. host and
user are regular expressions or nil
, interpreted as a
regular expression which always matches.
proxy is a literal TRAMP file name whose local name part is ignored, and the method and user name parts are optional.
The method must be an inline method (see Inline methods). If
proxy is nil
, no additional hop is required reaching
user@host.
For example, to pass through the host ‘bastion.your.domain’ as user ‘bird’ to reach remote hosts outside the local domain:
(add-to-list 'tramp-default-proxies-alist '("\\." nil "/ssh:bird@bastion.your.domain:")) (add-to-list 'tramp-default-proxies-alist '("\\.your\\.domain\\'" nil nil))
Note: add-to-list
adds elements at the beginning of a
list. Therefore, most relevant rules must come last in the list.
Proxy hosts can be cascaded in the alist. If there is another host called ‘jump.your.domain’, which is the only host allowed to connect to ‘bastion.your.domain’, then:
(add-to-list 'tramp-default-proxies-alist '("\\`bastion\\.your\\.domain\\'" "\\`bird\\'" "/ssh:jump.your.domain:"))
proxy can take patterns %h
or %u
for host or
user respectively. Ports or domains, if they are part of
a hop file name, are not expanded by those patterns.
To login as ‘root’ on remote hosts in the domain ‘your.domain’, but login as ‘root’ is disabled for non-local access, then use this alist entry:
(add-to-list 'tramp-default-proxies-alist '("\\.your\\.domain\\'" "\\`root\\'" "/ssh:%h:"))
Opening /sudo:randomhost.your.domain: first connects
to ‘randomhost.your.domain’ via ssh
under your account
name, and then performs sudo -u root
on that host.
It is key for the sudo method in the above example to be applied on the host after reaching it and not on the local host. TRAMP checks therefore, that the host name for such hops matches the host name of the previous hop.
host, user and proxy can also take Lisp forms. These
forms when evaluated must return either a string or nil
.
To generalize (from the previous example): For all hosts, except my
local one, first connect via ssh
, and then apply
sudo -u root
:
(add-to-list 'tramp-default-proxies-alist '(nil "\\`root\\'" "/ssh:%h:")) (add-to-list 'tramp-default-proxies-alist `(,(regexp-quote (system-name)) nil nil))
Passing through hops involves dealing with restricted shells, such as
rbash
. If TRAMP is made aware, then it would use
them for proxies only.
An alist of regular expressions of hosts running restricted shells,
such as rbash
. TRAMP will then use them only as
proxies.
To specify the bastion host from the example above as running a restricted shell:
(add-to-list 'tramp-restricted-shell-hosts-alist "\\`bastion\\.your\\.domain\\'")
Sometimes, it is not possible to reach a remote host directly. A firewall might be in the way, which could be passed via a proxy server.
Both OpenSSH and PuTTY support such proxy settings, using an HTTP
tunnel via the CONNECT
command (conforming to RFC 2616, 2817
specifications). Proxy servers using HTTP 1.1 or later protocol
support this command.
With ssh
, you could use the ProxyCommand entry in
~/.ssh/config:
Host host.other.domain ProxyCommand nc -X connect -x proxy.your.domain:3128 %h %p
nc
is BSD’s netcat program, which establishes HTTP tunnels.
Any other program with such a feature could be used as well.
In the example, opening /ssh:host.your.domain: passes the HTTP proxy server ‘proxy.your.domain’ on port 3128.
PuTTY does not need an external program, HTTP tunnel support is built-in. In the PuTTY config program, create a session for ‘host.your.domain’. In the Connection/Data entry, select the HTTP option, and add ‘proxy.your.domain’ as Proxy hostname, and 3128 as Port.
Opening /plinkx:host.your.domain: passes the HTTP proxy server ‘proxy.your.domain’ on port 3128.
The tramp-methods
variable currently has an exhaustive list of
predefined methods. Any part of this list can be modified with more
suitable settings. Refer to the Lisp documentation of that variable,
accessible with C-h v tramp-methods RET.
In the ELPA archives, there are several examples of such extensions. They can be installed with Emacs’s Package Manager. This includes
Integration for LXC containers. A container is accessed via /lxc:container:/path/to/file, ‘container’ has the same meaning as with the docker method. A ‘user’ specification is ignored.
Integration for LXD containers. A container is accessed via /lxd:user@container:/path/to/file, ‘user’ and ‘container’ have the same meaning as with the docker method.
Browsing Git repositories with magit
. A versioned file is
accessed via /git:rev@root-dir:/path/to/file.
‘rev’ is a Git revision, and ‘root-dir’ is a virtual host
name for the root directory, specified in
magit-tramp-hosts-alist
.
Access of a hadoop/hdfs file system. A file is accessed via /hdfs:user@node:/path/to/file, where ‘user’ is the user that you want to use, and ‘node’ is the name of the hadoop server.
Convenience method to access vagrant boxes. It is often used in multi-hop file names like /vagrant:box|sudo:box:/path/to/file, where ‘box’ is the name of the vagrant box.
tramp-completion-function-alist
uses predefined files for user
and host name completion (see File name completion). For each
method, it keeps a set of configuration files and a function that can
parse that file. Each entry in tramp-completion-function-alist
is of the form (method pair1 pair2 …).
Each pair is composed of (function file). function is responsible for extracting user names and host names from file for completion. There are two functions which access this variable:
This function returns the list of completion functions for method.
Example:
(tramp-get-completion-function "rsh") ⇒ ((tramp-parse-rhosts "/etc/hosts.equiv") (tramp-parse-rhosts "~/.rhosts"))
This function sets function-list as list of completion functions for method.
Example:
(tramp-set-completion-function "ssh" '((tramp-parse-sconfig "/etc/ssh_config") (tramp-parse-sconfig "~/.ssh/config"))) ⇒ ((tramp-parse-sconfig "/etc/ssh_config") (tramp-parse-sconfig "~/.ssh/config"))
The following predefined functions parsing configuration files exist:
tramp-parse-rhosts
¶This function parses files which are syntactical equivalent to ~/.rhosts. It returns both host names and user names, if specified.
tramp-parse-shosts
¶This function parses files which are syntactical equivalent to ~/.ssh/known_hosts. Since there are no user names specified in such files, it can return host names only.
tramp-parse-sconfig
¶This function returns the host nicknames defined by Host entries in ~/.ssh/config style files.
tramp-parse-shostkeys
¶SSH2 parsing of directories /etc/ssh2/hostkeys/* and
~/ssh2/hostkeys/*. Hosts are coded in file names
hostkey_portnumber_host-name.pub. User names
are always nil
.
tramp-parse-sknownhosts
¶Another SSH2 style parsing of directories like
/etc/ssh2/knownhosts/* and ~/ssh2/knownhosts/*. This
case, hosts names are coded in file names
host-name.algorithm.pub. User names are always nil
.
tramp-parse-hosts
¶A function dedicated to /etc/hosts for host names.
tramp-parse-passwd
¶A function which parses /etc/passwd for user names.
tramp-parse-etc-group
¶A function which parses /etc/group for group names.
tramp-parse-netrc
¶A function which parses ~/.netrc and ~/.authinfo-style files.
To keep a custom file with custom data in a custom structure, a custom function has to be provided. This function must meet the following conventions:
file must be either a file on the host, or nil
. The
function must return a list of (user host), which are
taken as candidates for completion for user and host names.
Example:
(my-tramp-parse "~/.my-tramp-hosts") ⇒ ((nil "toto") ("daniel" "melancholia"))
To avoid repeated prompts for passwords, consider native caching
mechanisms, such as ssh-agent
for ssh-like
methods, or pageant
for plink-like methods.
TRAMP offers alternatives when native solutions cannot meet the need.
The package auth-source.el, originally developed for No Gnus,
reads passwords from different sources, See auth-source. The default authentication file is
~/.authinfo.gpg, but this can be changed via the user option
auth-sources
.
A typical entry in the authentication file:
machine melancholia port scp login daniel password geheim
The port can take any TRAMP method (see Inline methods, see External methods). Omitting port values matches all TRAMP methods. Domain and ports, as used in TRAMP file name syntax, must be appended to the machine and login items:
machine melancholia#4711 port davs login daniel%BIZARRE password geheim
For the methods doas, sudo, sudoedit and nspawn the password of the user requesting the connection is needed, and not the password of the target user3. If these connections happen on the local host, an entry with the local user and local host is used:
machine host port sudo login user password secret
user and host are the strings returned by
(user-login-name)
and (system-name)
. If one of these
methods is connected via a multi-hop (see Connecting to a remote host using multiple hops), the
credentials of the previous hop are used.
If no proper entry exists, the password is read
interactively. After successful login (verification of the password),
Emacs offers to save a corresponding entry for further use by
auth-source
backends which support this. This can be changed
by setting the user option auth-source-save-behavior
to nil
.
Set auth-source-debug
to t
to debug messages.
Note that auth-source.el is not used for ftp
connections, because TRAMP passes the work to Ange FTP. If
you want, for example, use your ~/.authinfo.gpg authentication
file, you must customize ange-ftp-netrc-filename
:
(customize-set-variable 'ange-ftp-netrc-filename "~/.authinfo.gpg")
In case you do not want to use an authentication file for TRAMP passwords, use connection-local variables like this:
(connection-local-set-profile-variables 'remote-without-auth-sources '((auth-sources . nil)))
(connection-local-set-profiles '(:application tramp) 'remote-without-auth-sources)
TRAMP can cache passwords as entered and reuse when needed for the same user or host name independent of the access method.
password-cache-expiry
sets the duration (in seconds) the
passwords are remembered. Passwords are never saved permanently nor
can they extend beyond the lifetime of the current Emacs session. Set
password-cache-expiry
to nil
to disable expiration.
Set password-cache
to nil
to disable password caching.
For faster initial connection times, TRAMP stores previous
connection properties in a file specified by the user option
tramp-persistency-file-name
.
The default file name for tramp-persistency-file-name
is
~/.emacs.d/tramp.
TRAMP reads this file during Emacs startup, and writes to it when exiting Emacs. Delete this file for TRAMP to recreate a new one on next Emacs startup.
Set tramp-persistency-file-name
to nil
to disable
storing connections persistently.
When TRAMP detects a change in the operating system version in
a remote host (via the command uname -sr
), it flushes all
connection related information for that host and creates a new entry.
For more precise customization, parameters specified by
tramp-methods
can be overwritten manually.
Set tramp-connection-properties
to manually override
tramp-methods
. Properties in this list are in the form
(regexp property value)
. regexp
matches remote file names. Use nil
to match all.
property is the property’s name, and value is the
property’s value.
property is any method specific parameter contained in
tramp-methods
. The parameter key in tramp-methods
is a
symbol name tramp-<foo>
. To overwrite that property, use the
string "<foo>"
for property. For example, this changes the
remote shell:
(add-to-list 'tramp-connection-properties (list (regexp-quote "/ssh:user@randomhost.your.domain:") "remote-shell" "/bin/ksh"))
(add-to-list 'tramp-connection-properties (list (regexp-quote "/ssh:user@randomhost.your.domain:") "remote-shell-login" '("-")))
The parameters tramp-remote-shell
and
tramp-remote-shell-login
in tramp-methods
now have new
values for the remote host.
property could also be any property found in
tramp-persistency-file-name
.
Not all connection properties need to be changed. The most relevant properties are listed here:
"login-program"
The property "login-program"
stores the program to be used to
connect to the remote host. Sometimes, the program might have another
name on your host, or it might be located in another path. In this case,
you can overwrite the default value, which is special for every
connection method. It is used in all connection methods of
tramp-sh.el.
"login-args"
"login-args"
specifies a list of lists of arguments to pass to
"login-program"
. Read the docstring of tramp-methods
how
to construct these lists.
"remote-shell"
This property tells TRAMP which remote shell to apply on the
remote host. It is used in all connection methods of
tramp-sh.el. The default value is "/bin/sh"
.
"remote-shell-login"
A property to be used in conjunction with "remote-shell"
. It
specifies, which shell argument triggers a login shell. Its default
value is "-l"
, but some shells, like ksh
, prefer
"-"
.
"session-timeout"
All tramp-sh.el based methods accept the property
"session-timeout"
. This is the time (in seconds) after a
connection is disabled for security reasons, and must be
reestablished. A value of nil
disables this feature. Most of
the methods do not set this property except the sudo,
doas and run0 methods, which use predefined values.
"~"
"~user"
This is the home directory on the remote host. Setting this connection property helps especially for methods which cannot expand to a remote home directory, like adb, rclone and sshfs. Expanding ~ to home directory for an example.
"tmpdir"
The temporary directory on the remote host. If not specified, the
default value is "/data/local/tmp"
for the adb method,
"/C$/Temp"
for the smb method, and "/tmp"
otherwise.
Where temporary files are kept.
"posix"
Connections using the smb method check, whether the remote
host supports posix commands. If the remote host runs Samba, it
confirms this capability. However, some very old Samba versions have
errors in their implementation. In order to suppress the posix
commands for those hosts, the property "posix"
should be set to
nil
.
The default value of this property is t
(not specified in
tramp-methods
). If the remote host runs native MS Windows,
this property has no effect.
"mount-point"
The directory file name an FUSE-based file system is mounted
on. The default value of this property is
"<TMP>/tramp.method.user@host#port"
(not specified in
tramp-methods
). Where temporary files are kept.
"mount-args"
"copyto-args"
"moveto-args"
"about-args"
These properties keep optional flags to the different rclone
operations. See their default values in tramp-methods
if you
want to change their values.
TRAMP requires access to and rights to several commands on
remote hosts: ls
, test
, find
and
cat
.
Besides there are other required programs for Inline methods and External methods of connection.
To improve performance and accuracy of remote file access,
TRAMP uses perl
(or perl5
) and
grep
when available.
tramp-remote-path
specifies which remote directory paths
TRAMP can search for How TRAMP finds and uses programs on the remote host.
TRAMP uses standard defaults, such as /bin and
/usr/bin, which are reasonable for most hosts. To accommodate
differences in hosts and paths, for example, /bin:/usr/bin on
Debian GNU/Linux or
/usr/xpg4/bin:/usr/ccs/bin:/usr/bin:/opt/developerstudio12.6/bin on
Solaris, TRAMP queries the remote host with getconf
PATH
and updates the symbol tramp-default-remote-path
.
For instances where hosts keep obscure locations for paths for security reasons, manually add such paths to local .emacs as shown below for TRAMP to use when connecting.
(add-to-list 'tramp-remote-path "/usr/local/perl/bin")
Another way to find the remote path is to use the path assigned to the
remote user by the remote host. TRAMP does not normally retain
this remote path after login. However, tramp-own-remote-path
preserves the path value, which can be used to update
tramp-remote-path
.
(add-to-list 'tramp-remote-path 'tramp-own-remote-path)
Note that this works only if your remote /bin/sh
shell supports the login argument ‘-l’.
tramp-remote-path
can also be set per host via connection-local
variables.
You could define your own search directories like this:
(connection-local-set-profile-variables 'remote-path-with-bin '((tramp-remote-path . ("~/bin" tramp-default-remote-path))))
(connection-local-set-profile-variables 'remote-path-with-apply-pub-bin '((tramp-remote-path . ("/appli/pub/bin" tramp-default-remote-path))))
(connection-local-set-profiles '(:application tramp :machine "randomhost") 'remote-path-with-bin)
(connection-local-set-profiles '(:application tramp :user "anotheruser" :machine "anotherhost") 'remote-path-with-apply-pub-bin)
When remote search paths are changed, local TRAMP caches must be recomputed. To force TRAMP to recompute afresh, call M-x tramp-cleanup-this-connection RET or friends (see Cleanup remote connections).
By default, TRAMP uses the command /bin/sh
for
starting a shell on the remote host. This can be changed by setting
the connection property "remote-shell"
; see Setting own connection related information. If you want, for example, use
/usr/bin/zsh
on a remote host, you might apply
(add-to-list 'tramp-connection-properties (list (regexp-quote "/sshx:user@host:") "remote-shell" "/usr/bin/zsh"))
This works only for connection methods which allow overriding the remote login shell, like sshx or plink. See Inline methods and External methods for connection methods which support this.
This approach has also the advantage, that settings in
tramp-sh-extra-args
will be applied. For zsh
, the
trouble with the shell prompt due to set zle options will be avoided.
For bash
, loading ~/.editrc or ~/.inputrc is
suppressed.
Similar problems can happen with the local shell TRAMP uses to
create a process. By default, it uses the command /bin/sh
for this, which could also be a link to another shell. In order to
overwrite this, you might apply
(customize-set-variable 'tramp-encoding-shell "/usr/bin/zsh")
This uses also the settings in tramp-sh-extra-args
.
Note: If you use an ssh-based method for connection,
do not set the RemoteCommand option in your
ssh
configuration to something like screen
. If
used, RemoteCommand must open an interactive shell on the
remote host. On the other hand, some ssh-based methods, like
sshx or scpx, silently overwrite a
RemoteCommand option of the configuration file.
TRAMP checks for the availability of standard programs in the
usual locations. Common tactics include successively trying
test -e
, /usr/bin/test -e
, and /bin/test
-e
. ls -d
is another approach. But these approaches do not
help with these new login patterns.
When TRAMP encounters two-factor logins or additional challenge questions, such as entering birth date or security code or passphrase, TRAMP needs a few more configuration steps to accommodate them.
The difference between a password prompt and a passphrase prompt is that the password for completing the login while the passphrase is for authorizing access to local authentication information, such as the ssh key.
There is no one configuration to accommodate all the variations in login security, especially not the exotic ones. However, TRAMP provides a few tweaks to address the most common ones.
tramp-shell-prompt-pattern
¶tramp-shell-prompt-pattern
is for remote login shell prompt,
which may not be the same as the local login shell prompt,
shell-prompt-pattern
. Since most hosts use identical prompts,
TRAMP sets a similar default value for both prompts.
tramp-password-prompt-regexp
tramp-otp-password-prompt-regexp
tramp-wrong-passwd-regexp
¶TRAMP uses tramp-password-prompt-regexp
to
distinguish between prompts for passwords and prompts for passphrases.
By default, tramp-password-prompt-regexp
handles the
detection in English language environments. See a localization
example below:
(customize-set-variable 'tramp-password-prompt-regexp (concat "^.*" (regexp-opt '("passphrase" "Passphrase" ;; English "password" "Password" ;; Deutsch "passwort" "Passwort" ;; Français "mot de passe" "Mot de passe") t) ".*:\0? *"))
This user option is, by default, initialized from
password-word-equivalents
when TRAMP is loaded, and it
is usually more convenient to add new passphrases to that user option
instead of altering this user option.
The user option tramp-otp-password-prompt-regexp
has a similar
purpose, but for one-time passwords. Those passwords are not cached
by TRAMP for reuse.
Similar localization may be necessary for handling wrong password
prompts, for which TRAMP uses tramp-wrong-passwd-regexp
.
tramp-terminal-type
¶TRAMP uses the user option tramp-terminal-type
to set
the remote environment variable TERM
for the shells it runs.
By default, it is "dumb"
, but this could be changed. A dumb
terminal is best suited to run the background sessions of
TRAMP. However, running interactive remote shells might
require a different setting. This could be achieved by tweaking the
TERM
environment variable in process-environment
.
(let ((process-environment (cons "TERM=xterm-256color" process-environment))) (shell))
Sometimes, it is needed to identify whether a shell runs under
TRAMP control. The setting of environment variable TERM
will help:
if test "$TERM" = "dumb"; then ... fi
Another possibility is to check the environment variable
INSIDE_EMACS
. Like for all subprocesses of Emacs, this is set
to the version of the parent Emacs
process.
TRAMP adds its own package version to this string, which could
be used for further tests in an inferior shell. The string of that
environment variable looks always like
echo $INSIDE_EMACS ⇒ 27.2,tramp:2.4.5
tset
and other questions ¶To suppress inappropriate prompts for terminal type, TRAMP
sets the TERM
environment variable before the remote login
process begins via the user option tramp-terminal-type
(see
above). This will silence common tset
related prompts.
TRAMP’s strategy for handling such prompts (commonly triggered from login scripts on remote hosts) is to set the environment variables so that no prompts interrupt the shell initialization process.
An alternative approach is to configure TRAMP with strings
that can identify such questions using
tramp-actions-before-shell
. Example:
(defconst my-tramp-prompt-regexp "Enter the birth date of your mother:\\s-*" "Regular expression matching my login prompt question.")
(defun my-tramp-action (proc vec) "Enter \"19000101\" in order to give a correct answer." (save-window-excursion (with-current-buffer (tramp-get-connection-buffer vec) (tramp-message vec 6 "\n%s" (buffer-string)) (tramp-send-string vec "19000101"))))
(add-to-list 'tramp-actions-before-shell '(my-tramp-prompt-regexp my-tramp-action))
The regular expressions used in tramp-actions-before-shell
must
match the end of the connection buffer. Due to performance reasons,
this search starts at the end of the buffer, and it is limited to 256
characters backwards.
When a user name is the same as a variable name in a local file, such
as .profile, then TRAMP may send incorrect values for
environment variables. To avoid incorrect values, change the local
variable name to something different from the user name. For example,
if the user name is FRUMPLE
, then change the variable name to
FRUMPLE_DIR
.
When the remote host’s .profile is also used for shells other than Bourne shell, then some incompatible syntaxes for commands in .profile may trigger errors in Bourne shell on the host and may not complete client’s TRAMP connections.
One example of a Bourne shell incompatible syntax in .profile:
using export FOO=bar
instead of FOO=bar; export
FOO
. After remote login, TRAMP will trigger an error during
its execution of /bin/sh
on the remote host because Bourne
shell does not recognize the export command as entered in
.profile.
Likewise, (‘~’) character in paths will cause errors because Bourne shell does not do (‘~’) character expansions.
One approach to avoiding these incompatibilities is to make all commands in ~/.shrc and ~/.profile Bourne shell compatible so TRAMP can complete connections to that remote. To accommodate using non-Bourne shells on that remote, use other shell-specific config files. For example, bash can use ~/.bash_profile and ignore .profile.
TRAMP redefines the remote shell prompt internally for robust parsing. This redefinition affects the looks of a prompt in an interactive remote shell through commands, such as M-x shell RET. Such prompts, however, can be reset to something more readable and recognizable using these environment variables.
TRAMP sets the INSIDE_EMACS
environment variable in the
startup script file ~/.emacs_SHELLNAME.
SHELLNAME
is bash
or equivalent shell names. Change it by
setting the environment variable ESHELL
in the .emacs as
follows:
(setenv "ESHELL" "bash")
Then re-set the prompt string in ~/.emacs_SHELLNAME as follows:
# Reset the prompt for remote TRAMP shells.
if [ "${INSIDE_EMACS/*tramp*/tramp}" == "tramp" ] ; then
PS1="[\u@\h \w]$ "
fi
busybox
/ nc
¶TRAMP’s nc method uses the nc
command to
install and execute a listener as follows (see tramp-methods
):
$ nc -l -p 42
The above command-line syntax has changed with busybox
versions. If nc
refuses the ‘-p’ parameter, then
overwrite as follows:
(add-to-list 'tramp-connection-properties `(,(regexp-quote "192.168.0.1") "remote-copy-args" (("-l") ("%r"))))
where ‘192.168.0.1’ is the remote host IP address (see Setting own connection related information).
The most common TRAMP connection family is based on either
ssh
or scp
of OpenSSH, or plink
or
pscp
of PuTTY on MS Windows. In the following, some
configuration recommendations are given.
OpenSSH configuration files can use an Include option for further configuration files. Default TRAMP host name completion ignores this option. However, you can configure this yourself.
Given, your ~/.ssh/config file contains the following option:
Include ~/.ssh/conf.d/*
The following code snippet in your .emacs uses all files in that directory for host name completion:
(tramp-set-completion-function "ssh" (append (tramp-get-completion-function "ssh") (mapcar (lambda (file) `(tramp-parse-sconfig ,file)) (directory-files "~/.ssh/conf.d/" 'full directory-files-no-dot-files-regexp))))
This code snippet does it for the ssh method. If you replace
"ssh"
by "scp"
, it does it also for that method (or any other
method you like).
ssh
sessions on the local host hang when the network is
down. TRAMP cannot safely detect such hangs. OpenSSH can be
configured to kill such hangs with the following settings in
~/.ssh/config:
Host * ServerAliveInterval 5 ServerAliveCountMax 2
The corresponding PuTTY configuration is in the Connection entry, Seconds between keepalives option. Set this to 5. There is no counter which could be set.
TRAMP uses the ControlMaster=auto OpenSSH option by
default, if possible. However, it overwrites ControlPath
settings when initiating ssh
sessions. TRAMP does
this to fend off a stall if a master session opened outside the Emacs
session is no longer open. That is why TRAMP prompts for the
password again even if there is an ssh
already open.
Some OpenSSH versions support a ControlPersist option, which
allows you to set the ControlPath provided the variable
tramp-ssh-controlmaster-options
is customized as follows:
(customize-set-variable 'tramp-ssh-controlmaster-options (concat "-o ControlPath=/tmp/ssh-ControlPath-%%r@%%h:%%p " "-o ControlMaster=auto -o ControlPersist=yes"))
Note how ‘%r’, ‘%h’ and ‘%p’ must be encoded as ‘%%r’, ‘%%h’ and ‘%%p’.
Using a predefined string in tramp-ssh-controlmaster-options
,
or puzzling an own string, happens only when user option
tramp-use-connection-share
is set to t
. If the
~/.ssh/config file is configured appropriately for the above
behavior, then any changes to ssh
can be suppressed with
this nil
setting:
(customize-set-variable 'tramp-use-connection-share nil)
Sometimes, it is not possible to use OpenSSH’s ControlMaster
option for remote processes. This could result in concurrent access
to the OpenSSH socket when reading data by different processes, which
could block Emacs. In this case, setting
tramp-use-connection-share
to suppress
disables shared
access. It is not needed to set this user option permanently to
suppress
, binding the user option prior calling
make-process
is sufficient. TRAMP does this for
esxample for compilation processes on its own.
tramp-use-connection-share
should also be set to nil
or
suppress
if you use the ProxyCommand or
ProxyJump options in your ssh
configuration.
In order to use the ControlMaster option, TRAMP must
check whether the ssh
client supports this option. This is
only possible on the local host, for the first hop. TRAMP
does not use this option on proxy hosts, therefore.
If you want to use this option also for the other hops, you must configure ~/.ssh/config on the proxy host:
Host * ControlMaster auto ControlPath tramp.%C ControlPersist no
Check the ‘ssh_config(5)’ man page whether these options are supported on your proxy host.
On MS Windows, tramp-use-connection-share
is set to nil
by default, because the MS Windows and MSYS2 implementations of
OpenSSH
do not support this option properly.
In PuTTY, you can achieve connection sharing in the
Connection/SSH entry, enabling the Share SSH
connections if possible option. tramp-use-connection-share
must be set to nil
. If tramp-use-connection-share
is
set to t
or suppress
, plink
is called with the
option -share or -noshare, respectively.
TRAMP uses a temporary local copy when copying two files between different remote hosts via external methods. This behavior is due to authentication problems TRAMP cannot handle sufficiently. However, for scp connections this can be changed. When a file shall be copied between two different remote hosts ‘source’ and ‘target’, and
tramp-use-scp-direct-remote-copying
is non-nil
,
scp
running on host ‘source’ can authenticate to host
‘target’ without requiring a password,
TRAMP applies direct remote copying between hosts ‘source’ and ‘target’ like
scp -p -T -R -q -r source:/path/to/file target:/path/to/another/file
This protects also your local temporary directory from overrun when copying large files.
If these conditions do not apply, and
tramp-use-scp-direct-remote-copying
is non-nil
, the
option ‘-3’ is used instead of ‘-R’.
When TRAMP uses direct remote copying, password caches are not consulted.
This section is incomplete. Please share your solutions.
MS Windows’ ssh
does not open a remote TTY. Use the method
sshx or scpx instead. Furthermore, it cannot read a
passphrase for ssh private keys. Use the MS ssh-agent
.
Cygwin’s ssh
works only with a Cygwin version of Emacs. To
check for compatibility: type M-x eshell RET, and start
ssh test.host RET. Incompatibilities trigger this
message:
Pseudo-terminal will not be allocated because stdin is not a terminal.
Some older versions of Cygwin’s ssh
work with the
sshx access method. Consult Cygwin’s FAQ at
https://cygwin.com/faq/ for details.
On the Emacs
Wiki it is explained how to use the helper program
fakecygpty
to fix this problem.
When using the scpx access method, Emacs may call
scp
with MS Windows file naming, such as c:/foo. But
the version of scp
that is installed with Cygwin does not
know about MS Windows file naming, which causes it to incorrectly look
for a host named ‘c’.
A workaround: write a wrapper script for scp to convert Windows file names to Cygwin file names.
When using the cygwin ssh-agent
on MS Windows for
password-less interaction, ssh methods depend on the
environment variable SSH_AUTH_SOCK
. But this variable is not
set when Emacs is started from a Desktop shortcut and authentication
fails.
One workaround is to use an MS Windows based SSH Agent, such as the
native MS ssh-agent
or Pageant
. The latter is
part of the PuTTY Suite of tools.
The fallback is to start Emacs from a shell.
The FUSE file systems are mounted by default at
"<TMP>/tramp.method.user@host#port"
.4 Method is either "rclone"
or "sshfs"
. The user
name and port number are optional. If the file system is already
mounted, it will be used as it is. If the mount point does not exist
yet, TRAMP creates this directory.
The mount point can be overwritten by the connection property
"mount-point"
, see Setting own connection related information.
Example:
(add-to-list 'tramp-connection-properties `(,(regexp-quote "/sshfs:user@host:") "mount-point" ,(expand-file-name "sshfs.user@host" user-emacs-directory)))
The user option tramp-fuse-unmount-on-cleanup
, when set to
non-nil
, controls, whether a mount point is unmounted on
connection cleanup or on Emacs exiting.
The default arguments of the rclone
operations
mount
, copyto
, moveto
and
about
are declared in the variable tramp-methods
as
method specific parameters. Usually, they don’t need to be overwritten.
If needed, these parameters can be overwritten as connection
properties "mount-args"
, "copyto-args"
, "moveto-args"
and
"about-args"
, See Setting own connection related information. All of
them are list of strings.
Be careful changing "--dir-cache-time"
, this could delay
visibility of files.
The method sshfs declares the mount arguments in the variable
tramp-methods
, passed to the sshfs
command. This is
a list of list of strings, and can be overwritten by the connection
property "mount-args"
, See Setting own connection related information.
Additionally, it declares also the arguments for running remote
processes, using the ssh
command. These don’t need to be
changed.
TRAMP uses the adb method to access Android devices.
Android devices provide a restricted shell access through an USB
connection. The local host must have the adb
program
installed. Usually, it is sufficient to open the file
/adb::/. Then you can navigate in the file system via
dired
.
Alternatively, applications such as Termux
or SSHDroid
that run sshd
process on the Android device can accept any
ssh-based methods provided these settings are adjusted:
sh
must be specified for remote shell since Android devices
do not provide /bin/sh
. sh
will then invoke
whatever shell is installed on the device with this setting:
(add-to-list 'tramp-connection-properties (list (regexp-quote "192.168.0.26") "remote-shell" "sh"))
where ‘192.168.0.26’ is the Android device’s IP address. (see Setting own connection related information).
Termux
case. You must adapt the file names in
tramp-remote-path
, for example via connection-local
settings:
(connection-local-set-profile-variables 'tramp-connection-local-termux-profile `((tramp-remote-path . ,(mapcar (lambda (x) (if (stringp x) (concat "/data/data/com.termux/files" x) x)) (copy-tree tramp-remote-path))))) (connection-local-set-profiles '(:application tramp :machine "192.168.0.26") 'tramp-connection-local-termux-profile)
(add-to-list 'tramp-connection-properties (list (regexp-quote "192.168.0.26") "tmpdir" "/data/data/com.termux/files/home/tmp"))
sshd
is
listening on port ‘2222’.
To add a corresponding entry to the ~/.ssh/config file (recommended), use this:
Host android HostName 192.168.0.26 User root Port 2222
To use the host name ‘android’ instead of the IP address shown in the previous example, fix the connection properties as follows:
(add-to-list 'tramp-connection-properties (list (regexp-quote "android") "remote-shell" "sh")) (add-to-list 'tramp-connection-properties (list (regexp-quote "android") "tmpdir" "/data/data/com.termux/files/home/tmp")) (connection-local-set-profiles '(:application tramp :machine "android") 'tramp-connection-local-termux-profile)
Open a remote connection with the more concise command C-x C-f /ssh:android: RET.
With the kubernetes method, containers in Kubernetes pods can be accessed. The host name is a pod name returned by ‘kubectl get pods’, or ‘container.pod’ if an explicit container name shall be used. Otherwise, the first container in a pod is used.
Sometimes, asynchronous processes for a host without a dedicated container name show a warning like ‘Defaulted container "container1" out of: container1, container2’. This can be mitigated by setting the pod annotation ‘kubectl.kubernetes.io/default-container’ to a proper value (‘container1’ in this example).
TRAMP uses the default Kubernetes context and namespace. If
another context or namespace shall be used, configure the user options
tramp-kubernetes-context
and tramp-kubernetes-namespace
.
To avoid TRAMP from saving backup files owned by ‘root’
to locations accessible to others, default backup settings in
backup-directory-alist
have to be altered.
Here’s a scenario where files could be inadvertently exposed. Emacs by default writes backup files to the same directory as the original files unless changed to another location, such as ~/.emacs.d/backups/. Such a directory will also be used by default by TRAMP when using, say, a restricted file /su:root@localhost:/etc/secretfile. The backup file of the secretfile is now owned by the user logged in from TRAMP and not ‘root’.
When backup-directory-alist
is nil
(the default), such
problems do not occur.
To “turn off” the backup feature for remote files and stop TRAMP from saving to the backup directory, use this:
(add-to-list 'backup-directory-alist (cons tramp-file-name-regexp nil))
Disabling backups can be targeted to just the su and sudo methods:
(setq backup-enable-predicate (lambda (name) (and (normal-backup-enable-predicate name) (not (let ((method (file-remote-p name 'method))) (when (stringp method) (member method '("su" "sudo"))))))))
Another option is to create better backup file naming with user and
host names prefixed to the file name. For example, transforming
/etc/secretfile to
~/.emacs.d/backups/!su:root@localhost:!etc!secretfile, set the
TRAMP user option tramp-backup-directory-alist
from
the existing user option backup-directory-alist
.
Then TRAMP backs up to a file name that is transformed with a prefix consisting of the DIRECTORY name. This file name prefixing happens only when the DIRECTORY is an absolute local file name.
Example:
(add-to-list 'backup-directory-alist (cons "." "~/.emacs.d/backups/")) (customize-set-variable 'tramp-backup-directory-alist backup-directory-alist)
The backup file name of /su:root@localhost:/etc/secretfile would be /su:root@localhost:~/.emacs.d/backups/!su:root@localhost:!etc!secretfile~.
Just as for backup files, similar issues of file naming affect
auto-saving remote files. Auto-saved files are saved in the directory
specified by the user option auto-save-file-name-transforms
.
By default this is set to the local temporary directory. But in some
versions of Debian GNU/Linux, this points to the source directory
where the Emacs was compiled. Reset such values to a valid directory.
Set auto-save-file-name-transforms
to nil
to save
auto-saved files to the same directory as the original file.
Alternatively, set the user option tramp-auto-save-directory
to direct all auto saves to that location.
If you want to suppress auto-saving of remote files at all, set user
option remote-file-name-inhibit-auto-save
to non-nil
.
An alternative to auto-save-mode
is
auto-save-visited-mode
. In this mode, auto-saving is identical
to explicit saving. If you want to disable this behavior for remote
files, set user option
remote-file-name-inhibit-auto-save-visited
to non-nil
.
And still more issues to handle. Since Emacs 28, file locks use a
similar user option as auto-save files, called
lock-file-name-transforms
. By default this user option is
nil
, meaning to keep file locks in the same directory as the
original file.
If you change lock-file-name-transforms
in order to keep file
locks for remote files somewhere else, you will lose Emacs’s feature
to warn you, if a file is changed in parallel from different Emacs
sessions, or via different remote connections. Be careful with such
settings.
Setting remote-file-name-inhibit-locks
to non-nil
prevents the creation of remote lock files at all.
Per default, TRAMP asks for confirmation if a
‘root’-owned remote backup, auto-save or lock file has to be
written to your local temporary directory. If you want to suppress
this confirmation question, set user option
tramp-allow-unsafe-temporary-files
to t
.
Note: File encryption in TRAMP is experimental, don’t use it in production systems!
Sometimes, it is desirable to protect files located on remote directories, like cloud storages. In order to do this, you might instruct TRAMP to encrypt all files copied to a given remote directory, and to decrypt such files when accessing. This includes both file contents and file names.
TRAMP does this transparently. Although both files and file names are encrypted on the remote side, they are accessible inside Emacs as they wouldn’t be transformed as such.
Internally, TRAMP uses the encfs
package.
Therefore, this feature is available only if this package is installed
on the local host. TRAMP does not keep and ‘encfs
mountpoint’ permanently. Instead, it encrypts / decrypts files and
file names on the fly, using encfsctl
.
This command marks the existing remote directory name for encryption. Files in that directory and all subdirectories will be encrypted before copying to, and decrypted after copying from that directory. File and directory names will be also encrypted.
If a remote directory is marked for encryption, it is initialized via
encfs
the very first time a file in this directory is
accessed. This user option controls, which default encfs
configuration option will be selected, it can be "--standard"
or "--paranoia"
. See the ‘encfs(1)’ man page for details.
However, TRAMP must adapt these configuration sets. The chainedNameIV configuration option must be disabled; otherwise TRAMP couldn’t handle file name encryption transparently.
A password protected encfs configuration file is created the
very first time you access an encrypted remote directory. It is kept
in your user-emacs-directory
with the url-encoded directory
name as part of the basename, and encfs6.xml as suffix. If
you, for example, mark the remote directory
/nextcloud:user@host:/path/to/dir for encryption, the
configuration file is saved as
tramp-%2Fnextcloud%3Auser%40host%3A%2Fpath%2Fto%2Fdir%2F.encfs6.xml
in user-emacs-directory
. Do not lose this file and the
corresponding password; otherwise there is no way to decrypt your
encrypted files.
If this user option is non-nil
(the default), the encfs
configuration file .encfs6.xml is also kept in the encrypted
remote directory. It depends on you, whether you regard the password
protection of this file as sufficient. The advantage would be, that
such a remote directory could be accessed by different Emacs sessions,
different users, without presharing the configuration file between the
users.
The command encfsctl
, the workhorse for encryption /
decryption, needs the configuration file password every call.
Therefore, it is recommend to cache this password in Emacs. This can
be done using auth-sources
, see Using an authentication file.
An entry needs the url-encoded directory name as machine, your local
user name as user, and the password. The port is optional, if given
it must be the string "crypt"
. The example above would require
the following entry in the authentication file ("yourname"
is the
result of (user-login-name)
):
machine %2Fnextcloud%3Auser%40host%3A%2Fpath%2Fto%2Fdir%2F \ login yourname port crypt password geheim
If you use a remote file name with a quoted localname part, this localname and the corresponding file will not be encrypted / decrypted. If you have an encrypted remote directory /nextcloud:user@host:/path/to/dir, the command
C-x d /nextcloud:user@host:/path/to/dir
will show the directory listing with the plain file names, and the command
C-x d /nextcloud:user@host:/:/path/to/dir
will show the directory listing with the encrypted file names, and visiting a file will show its encrypted contents. However, it is highly discouraged to mix encrypted and not encrypted files in the same directory.
This command should be used to indicate that files in name
should no longer be encrypted. Existing encrypted files and
subdirectories will remain encrypted.
TRAMP operates transparently, accessing remote files as if they are local. However, TRAMP employs a formalized remote file naming syntax to perform its functions transparently. This syntax consists of many parts specifying access methods, authentication, host names, and file names. Ange FTP uses a similar syntax.
Unlike opening local files in Emacs, which are instantaneous, opening remote files in TRAMP is slower at first. Sometimes there is a noticeable delay before the prompts for passwords or authentication appear in the minibuffer. Hitting RET or other keys during this gap will be processed by Emacs. This type-ahead facility is a feature of Emacs that may cause missed prompts when using TRAMP.
/method:host:/path/to/file opens file /path/to/file on the remote host host, using the method method.
For the file .emacs located in the home directory, on the host ‘melancholia’, using method ssh.
For the file .emacs specified using the fully qualified domain name of the host.
For the file .emacs specified using the ~, which is expanded.
For the file .emacs located in ‘daniel’’s home directory on the host, ‘melancholia’. The ~<user> construct is expanded to the home directory of that user on the remote host.
For the file /etc/squid.conf on the host ‘melancholia’.
host can take IPv4 or IPv6 address, as in /ssh:127.0.0.1:.emacs or /ssh:[::1]:.emacs. For syntactical reasons, IPv6 addresses must be embedded in square brackets [ and ].
By default, TRAMP will use the current local user name as the remote user name for log in to the remote host. Specifying a different name using the proper syntax will override this default behavior: /method:user@host:path/to/file.
/ssh:daniel@melancholia:.emacs is for file .emacs in ‘daniel’’s home directory on the host, ‘melancholia’, accessing via method ssh.
For specifying port numbers, affix #<port> to the host name. For example: /ssh:daniel@melancholia#42:.emacs.
All method, user name, host name, port number and local name parts are optional, See Selecting a default method, See Selecting a default user, See Selecting a default host. For syntactical reasons, the default method must be indicated by the pseudo method -.
The syntax described in TRAMP file name conventions is the default
syntax, which is active after Emacs startup. However, this can be
changed.
This command changes the syntax TRAMP uses for remote file
names. Beside the default
value, syntax can be
simplified
This remote file name syntax is similar to the syntax used by Ange FTP. A remote file name has the form /user@host:path/to/file. The ‘user@’ part is optional, and the method is determined by Selecting a default method.
separate
This remote file name syntax originated in the XEmacs text editor. A remote file name has the form /[method/user@host]path/to/file. The ‘method’ and ‘user@’ parts are optional.
This variable keeps a regexp which matches the selected remote file
name syntax. Its value changes after every call of
tramp-change-syntax
. However, it is not recommended to use
this variable in external packages, a call of file-remote-p
is
much more appropriate.
TRAMP can complete the following TRAMP file name components: method names, user names, host names, and file names located on remote hosts.
For example, type C-x C-f / s TAB, TRAMP completion choices show up as
sbin/ | scp: | scpx: | sftp: | sg: |
smb: | srv/ | ssh: | sshx: | su: |
sudo: | sys/ |
‘ssh:’ is a possible completion for the respective method, and ‘sbin/’ stands for the directory /sbin on your local host.
Type s h : for the minibuffer completion to ‘/ssh:’. Typing TAB shows host names TRAMP extracts from ~/.ssh/config file, for example:
ssh:127.0.0.1: | ssh:192.168.0.1: |
ssh:[::1]: | ssh:localhost: |
ssh:melancholia.danann.net: | ssh:melancholia: |
Choose a host from the above list and then continue to complete file names on that host.
When the configuration (see Selecting config files for user/host name completion) includes user names, then the completion lists will account for the user names as well.
Results from auth-sources
search (see Using an authentication file) are added to the completion candidates. This
search could be annoying, for example due to a passphrase request of
the ~/.authinfo.gpg authentication file. The user option
tramp-completion-use-auth-sources
controls, whether such a
search is performed during completion.
Remote hosts previously visited or hosts whose connections are kept
persistently (see Reusing connection related information) will be included in the
completion lists. If you want to suppress this completion because
there are invalid entries in the persistency file, for example if the
host configuration changes often, or if you plug your laptop to
different networks frequently, you can set the user option
tramp-completion-use-cache
to nil
.
After remote host name completion comes completion of file names on the remote host. It works the same as with local host file completion except that killing with double-slash // kills only the file name part of the TRAMP file name syntax. A triple-slash stands for the default behavior.
Example:
C-x C-f /ssh:melancholia:/usr/local/bin//etc TAB -| /ssh:melancholia:/etc C-x C-f /ssh:melancholia://etc TAB -| /ssh:melancholia:/etc C-x C-f /ssh:melancholia:/usr/local/bin///etc TAB -| /etc
TRAMP file name syntax can accommodate ad-hoc specification of
multiple proxies without using tramp-default-proxies-alist
configuration setup (see Connecting to a remote host using multiple hops).
Each proxy is specified using the same syntax as the remote host specification minus the file name part. Each hop is separated by a ‘|’. Chain the proxies from the starting host to the destination remote host name and file name. For example, hopping over a single proxy ‘bird@bastion’ to a remote file on ‘you@remotehost’:
C-x C-f /ssh:bird@bastion|ssh:you@remotehost:/path RET
Each involved method must be an inline method (see Inline methods).
TRAMP adds the ad-hoc definitions on the fly to
tramp-default-proxies-alist
and is available for reuse during
that Emacs session. Subsequent TRAMP connections to the same
remote host can then use the shortcut form:
‘/ssh:you@remotehost:/path’.
If this user option is non-nil
, ad-hoc definitions are kept in
remote file names instead of showing the shortcuts.
(customize-set-variable 'tramp-show-ad-hoc-proxies t)
Ad-hoc definitions are removed from tramp-default-proxies-alist
via the command M-x tramp-cleanup-all-connections RET
(see Cleanup remote connections).
For ad-hoc definitions to be saved automatically in
tramp-default-proxies-alist
for future Emacs sessions, set
tramp-save-ad-hoc-proxies
to non-nil
.
(customize-set-variable 'tramp-save-ad-hoc-proxies t)
Ad-hoc proxies can take patterns %h
or %u
like in
tramp-default-proxies-alist
. The following file name expands
to user ‘root’ on host ‘remotehost’, starting with an
ssh session on host ‘remotehost’:
/ssh:%h|su:remotehost:.
On the other hand, if a trailing hop does not specify a host name, the host name of the previous hop is reused. Therefore, the following file name is equivalent to the previous example: /ssh:remotehost|su::.
When this list includes the last method in a multi-hop connection, the remote host will be queried for a list of completion candidates. This can, for example, provide a list of running docker or podman containers on the remote host.
(customize-set-variable 'tramp-completion-multi-hop-methods `(,tramp-docker-method ,tramp-podman-method))
A common use case for ad-hoc specifications is to visit a file or a
directory with proper permissions, for example with the sudo
method. The command tramp-revert-buffer-with-sudo
supports
this.
This command shows the current buffer with sudo permissions.
The buffer must either visit a file, or a directory
(dired-mode
).
The method tramp-revert-buffer-with-sudo
shows an alternate
buffer. It defaults to sudo, other valid methods are
su, doas, run0, and ksu.
(customize-set-variable 'tramp-file-name-with-method "doas")
These methods apply the user ‘root’ as default. If another user
shall be taken, add a proper rule to the user option
tramp-default-user-alist
(see Selecting a default user):
(add-to-list 'tramp-default-user-alist '("sudo" "remotehost" "admin"))
Home directories on remote hosts can be typed as tilde ~. If possible, they are expanded to the remote user’s home directory on the remote host. Example:
/ssh:user@host:~ ⇒ /ssh:user@host:/home/user
This works in general for ssh-like methods, and for sudoedit. These methods allow also the home directory expansion for another user, like
/sudoedit::~otheruser ⇒ /sudoedit:root@localhost:/home/otheruser
For other methods, a home directory can be expanded only if supported. This happens for example for the sftp method. Methods, which require a share directory in the remote file name (afp, smb), use the value of this share directory as home directory:
/smb:user@host:~ ⇒ /smb:user@host:/share
Since TRAMP cannot know in advance which share directory is intended to use, this expansion can be applied only when a share directory has been used already.
The methods adb, rclone and sshfs do not support home directory expansion at all. However, TRAMP keeps the home directory in the cache. Therefore, those methods could be configured to expand a home directory via a connection property, See Setting own connection related information. Example:
(add-to-list 'tramp-connection-properties (list (regexp-quote "/sshfs:user@randomhost.your.domain:") "~user" "/home/user"))
When your remote file name does not contain a ‘user’ part, the
connection property "~"
must be used instead.
TRAMP supports starting new running processes on the remote host for discovering remote file names. Emacs packages on the remote host need no specific modifications for TRAMP’s use.
This type of integration does not work with the ftp method,
and does not support the pty association as specified in
start-file-process
.
process-file
and start-file-process
work on the remote
host when the variable default-directory
is remote:
(let ((default-directory "/ssh:remote.host:")) (start-file-process "grep" (get-buffer-create "*grep*") "/bin/sh" "-c" "grep -e tramp *"))
For a local process, process-file
returns either the exit code
of the process, or a string describing a signal, when the process has
been interrupted. Since it cannot be determined reliably whether a
remote process has been interrupted, process-file
will always
returns the exit code for it. When the user option
process-file-return-signal-string
is non-nil
,
process-file
treats all exit codes greater than 128 as an
indication that the process has been interrupted, and returns a
corresponding string.
This remote process handling does not apply to GVFS
(see GVFS-based external methods) because the remote file system is mounted
on the local host and TRAMP accesses it by changing the
default-directory
.
TRAMP starts a remote process when a command is executed in a
remote file or directory buffer. As of now, these packages have been
integrated to work with TRAMP: shell.el,
eshell.el, compile.el (commands like compile
and
grep
) and gud.el (gdb
or perldb
).
TRAMP always modifies the INSIDE_EMACS
environment
variable for remote processes. By default, this environment variable
shows the Emacs version. TRAMP adds its own version string,
so it looks like ‘27.2,tramp:2.4.5.1’. However, other packages
might also add their name to this environment variable, like
‘27.2,comint,tramp:2.4.5.1’.
For TRAMP to find the command on the remote, it must be
accessible through the default search path as setup by TRAMP
upon first connection. Alternatively, use an absolute path or extend
tramp-remote-path
(see How TRAMP finds and uses programs on the remote host):
(add-to-list 'tramp-remote-path "~/bin") (add-to-list 'tramp-remote-path "/appli/pub/bin")
Customize user option tramp-remote-process-environment
to
suit the remote program’s environment for the remote host.
tramp-remote-process-environment
is a list of strings
structured similar to process-environment
, where each element
is a string of the form ‘ENVVARNAME=VALUE’.
To avoid any conflicts with local host environment variables set through local configuration files, such as ~/.profile, use ‘ENVVARNAME=’ to unset them for the remote environment.
Use add-to-list
to add entries:
(add-to-list 'tramp-remote-process-environment "JAVA_HOME=/opt/java")
Modifying or deleting already existing values in the
tramp-remote-process-environment
list may not be feasible on
restricted remote hosts. For example, some system administrators
disallow changing HISTORY
environment variable. To accommodate
such restrictions when using TRAMP, fix the
tramp-remote-process-environment
by the following code in the
local .emacs file:
(let ((process-environment tramp-remote-process-environment)) (setenv "HISTORY" nil) (setq tramp-remote-process-environment process-environment))
Setting the ENV
environment variable instructs some shells to
read an initialization file. By default, TRAMP disables
this. You can override this behavior by evaluating
(let ((process-environment tramp-remote-process-environment)) (setenv "ENV" "$HOME/.profile") (setq tramp-remote-process-environment process-environment))
In addition to tramp-remote-process-environment
, you can set
environment variables for individual remote process calls by
let-binding process-environment
. TRAMP applies any
entries not present in the global default value of
process-environment
(overriding
tramp-remote-process-environment
settings, if they conflict).
For example:
(let ((process-environment (cons "HGPLAIN=1" process-environment))) (process-file ...))
Let-binding in this way works regardless of whether the process to be
called is local or remote, since TRAMP would add just the
HGPLAIN
setting and local processes would take whole value of
process-environment
along with the new value of HGPLAIN
.
For integrating other Emacs packages so TRAMP can execute remotely, please file a bug report. See Reporting Bugs and Problems.
shell
on a remote hostshell-command
on a remote hosteshell
on a remote hostTo allow a remote program to create an X11 window on the local host,
set the DISPLAY
environment variable for the remote host as
follows in the local .emacs file:
(add-to-list 'tramp-remote-process-environment (format "DISPLAY=%s" (getenv "DISPLAY")))
(getenv "DISPLAY")
should return a recognizable name for the
local host that the remote host can redirect X11 window
interactions. If querying for a recognizable name is not possible for
whatever reason, then replace (getenv "DISPLAY")
with a
hard-coded, fixed name. Note that using ‘:0’ for X11 display name
here will not work as expected.
An alternate approach is specify ForwardX11 yes or
ForwardX11Trusted yes in ~/.ssh/config on the local
host. Furthermore, set tramp-use-connection-share
to
nil
(see Using ssh connection sharing), in order to avoid
unwanted side effects.
Due to the remote shell saving tilde expansions triggered by
TRAMP, the shell history file is probably growing rapidly.
TRAMP can suppress this behavior with the user option
tramp-histfile-override
. When set to t
, environment
variable HISTFILE
is unset, and environment variables
HISTFILESIZE
and HISTSIZE
are set to 0. Don’t use this
with bash
5.0.0. There is a bug in bash
which
lets bash
die.
Alternatively, tramp-histfile-override
could be a string.
Environment variable HISTFILE
is set to this file name then. Be
careful when setting to /dev/null; this might result in
undesired results when using bash
as remote shell.
Another approach is to disable TRAMP’s handling of the
HISTFILE
at all by setting tramp-histfile-override
to
nil
. In this case, saving history could be turned off by
putting this shell code in .bashrc or .kshrc:
if [ -f $HOME/.sh_history ] ; then /bin/rm $HOME/.sh_history fi if [ "${HISTFILE-unset}" != "unset" ] ; then unset HISTFILE fi if [ "${HISTSIZE-unset}" != "unset" ] ; then unset HISTSIZE fi
For ssh-based method, add the following line to your ~/.ssh/environment:
HISTFILE=/dev/null
shell
on a remote host ¶Set explicit-shell-file-name
to the appropriate shell name
when using TRAMP between two hosts with different operating
systems, such as ‘windows-nt’ and ‘gnu/linux’. This option
ensures the correct name of the remote shell program.
When explicit-shell-file-name
is equal to nil
, calling
shell
interactively will prompt for a shell name.
You could use connection-local variables for setting different values
of explicit-shell-file-name
for different remote hosts.
(connection-local-set-profile-variables 'remote-bash '((explicit-shell-file-name . "/bin/bash") (explicit-bash-args . ("-i"))))
(connection-local-set-profile-variables 'remote-ksh '((explicit-shell-file-name . "/bin/ksh") (explicit-ksh-args . ("-i"))))
(connection-local-set-profiles '(:application tramp :protocol "ssh" :machine "localhost") 'remote-bash)
(connection-local-set-profiles `(:application tramp :protocol "sudo" :user "root" :machine ,(system-name)) 'remote-ksh)
The command shell
reads the remote history file in order to to
initialize the history input ring. You can set the user option
shell-history-file-name
in order to specify which remote
history file is taken, or whether to suppress this at all. It accepts
the same values as tramp-histfile-override
, see see Managing remote shell history. shell-history-file-name
accepts also
connection-local values in shell
buffers.
shell-command
on a remote host ¶shell-command
executes commands synchronously or asynchronously
on remote hosts and displays output in buffers on the local
host. Example:
C-x C-f /sudo:: RET M-& tail -f /var/log/syslog.log RET
tail
command outputs continuously to the local buffer whose
name is the value of the variable shell-command-buffer-name-async
.
M-x auto-revert-tail-mode RET runs similarly showing continuous output.
shell-command
uses the user option shell-file-name
and
the variable shell-command-switch
in order to determine which
shell to run. For remote hosts, their default values are
/bin/sh and -c, respectively (except for the
adb method, which uses /system/bin/sh). Like the
variables in the previous section, these variables can be changed via
connection-local variables.
TRAMP cares about the user option
async-shell-command-width
for asynchronous shell commands. It
specifies the number of display columns for command output. For
synchronous shell commands, a similar effect can be achieved by adding
the environment variable COLUMNS
to
tramp-remote-process-environment
.
eshell
on a remote host ¶TRAMP is integrated into eshell.el, which enables
interactive eshell sessions on remote hosts at the command prompt.
You must add the module eshell-tramp
to
eshell-modules-list
. Here’s a sample interaction after opening
M-x eshell RET on a remote host:
~ $ cd /sudo::/etc RET /sudo:root@host:/etc $ hostname RET host /sudo:root@host:/etc $ id RET uid=0(root) gid=0(root) groups=0(root) /sudo:root@host:/etc $ find-file shadow RET #<buffer shadow> /sudo:root@host:/etc $
eshell
added custom su
and sudo
commands that set
the default directory correctly for the *eshell* buffer.
TRAMP silently updates tramp-default-proxies-alist
with an entry for this directory (see Connecting to a remote host using multiple hops):
~ $ cd /ssh:user@remotehost:/etc RET /ssh:user@remotehost:/etc $ find-file shadow RET File is not readable: /ssh:user@remotehost:/etc/shadow /ssh:user@remotehost:/etc $ sudo find-file shadow RET #<buffer shadow>
/ssh:user@remotehost:/etc $ su - RET /su:root@remotehost:/root $ id RET uid=0(root) gid=0(root) groups=0(root) /su:root@remotehost:/root $
gud.el provides a unified interface to symbolic
debuggers.
TRAMP can run debug on remote hosts by calling gdb
with a remote file name:
M-x gdb RET Run gdb (like this): gdb -i=mi /ssh:host:~/myprog RET
Since the remote gdb
and gdb-inferior
processes do not
belong to the same process group on the remote host, there will be a
warning, which can be ignored:
&"warning: GDB: Failed to set controlling terminal: Operation not permitted\n"
As consequence, there will be restrictions in I/O of the process to be debugged.
Relative file names are based on the remote default directory. When myprog.pl exists in /ssh:host:/home/user, valid calls include:
M-x perldb RET Run perldb (like this): perl -d myprog.pl RET
Just the local part of a remote file name, such as perl -d
/home/user/myprog.pl
, is not possible.
Arguments of the program to be debugged must be literal, can take relative or absolute paths, but not remote paths.
winexe
runs processes on a remote MS Windows host, and
TRAMP can use it for process-file
and
start-file-process
.
tramp-smb-winexe-program
specifies the local winexe
command. Powershell V2.0 on the remote host is required to run
processes triggered from TRAMP.
explicit-shell-file-name
and explicit-*-args
have to
be set properly so M-x shell RET can open a proper remote
shell on a MS Windows host. To open cmd
, set it as follows:
(setq explicit-shell-file-name "cmd" explicit-cmd-args '("/q"))
To open powershell
as a remote shell, use this:
(setq explicit-shell-file-name "powershell" explicit-powershell-args '("-file" "-"))
Asynchronous processes behave differently based on whether they use a
pseudo tty or not. This is controlled by the variable
process-connection-type
, which can be t
or pty
(use a pseudo tty), or nil
or pipe
(don’t use one).
TRAMP is based on running shells on the remote host, which
requires a pseudo tty. Therefore, it declares the variable
tramp-process-connection-type
, which carries this information
for remote processes. Its default value is t
, and there is no
need to change it. The name of the remote pseudo tty is returned by
the function process-tty-name
.
If a remote process, started by start-file-process
, should
not use a pseudo tty, this can be requested by setting
process-connection-type
to nil
or pipe
. There is
still a pseudo tty for the started process, but some terminal
properties are changed, like suppressing translation of carriage
return characters into newline.
The function make-process
allows controlling this explicitly by
using the :connection-type
keyword. If this keyword is not
used, the value of process-connection-type
is applied instead.
When available, TRAMP adds process properties to process objects of asynchronous properties. However, it is not guaranteed that all these properties are set.
remote-tty
This is the name of the terminal a process uses on the remote host, i.e., it reads and writes on.
remote-pid
The process id of the command executed on the remote host. This is used when sending signals remotely.
remote-command
The remote command which has been invoked via make-process
or
start-file-process
, a list of strings (program and its
arguments). This does not show the additional shell sugar
TRAMP makes around the commands, in order to see this you must
inspect TRAMP traces.
The functions list-system-processes
and
process-attributes
return information about system processes on
the respective remote host. In order to retrieve this information,
they use the command ps
, driven by the following constants:
This is a list of arguments (strings) ps
is called with.
The default value is appropriate for GNU/Linux remote hosts.
This is a list of cons cells (key . type)
for
interpretation of the ps
output. key is a key used in
the process-attributes
output plus the key pid
, and
type is the respective value returned by ps
. It can
be
• numberp | — a number |
• stringp | — a string without spaces |
• number | — a string of number width, could contain spaces |
• nil | — a string until end of line |
The default value is appropriate for GNU/Linux remote hosts.
If, for example, tramp-process-attributes-ps-args
is declared
as ("-eww" "-o" "pid,euid,euser,egid,egroup,comm:40,state")
,
the output of the respective ps
command would look like
PID EUID EUSER EGID EGROUP COMMAND S 1 0 root 0 root systemd S 1610 0 root 0 root NFSv4 callback S ...
The corresponding tramp-process-attributes-ps-format
has the value
((pid . numberp) (euid . numberp) (user . stringp)
(egid . numberp) (group . stringp) (comm . 40) (state . stringp))
The default values for tramp-process-attributes-ps-args
and
tramp-process-attributes-ps-format
can be overwritten by
connection-local variables.
This is already done by TRAMP for the adb method, see
tramp-adb-connection-local-default-ps-profile
and
tramp-adb-connection-local-default-ps-variables
.
There are three further predefined sets of connection-local variables
for remote BSD systems, for remote macOS systems, and for a remote
ps
command implemented with busybox
. These are
called tramp-connection-local-*-ps-profile
and
tramp-connection-local-*-ps-variables
. Use them like
(connection-local-set-profiles '(:application tramp :machine "mybsdhost") 'tramp-connection-local-bsd-ps-profile)
If you want to see a listing of remote system processes when calling
proced
, set user option proced-show-remote-processes
to
non-nil
, or invoke that command with a negative argument like
C-u - M-x proced RET when your buffer has a remote
default-directory
.
TRAMP’s implementation of make-process
and
start-file-process
requires a serious overhead for
initialization, every process invocation. This is needed for handling
interactive dialogs when connecting the remote host (like providing
a password), and initial environment setup.
Sometimes, this is not needed. Instead of starting a remote shell and
running the command afterwards, it is sufficient to run the command
directly. TRAMP supports this by an alternative
implementation of make-process
and start-file-process
.
This is triggered by the connection-local variable
tramp-direct-async-process
,
which must be set to a non-nil
value. Example:
(connection-local-set-profile-variables 'remote-direct-async-process '((tramp-direct-async-process . t)))
(connection-local-set-profiles '(:application tramp :machine "remotehost") 'remote-direct-async-process)
Using direct asynchronous processes in TRAMP is not possible, if the remote host is connected via multiple hops (see Connecting to a remote host using multiple hops). In this case, TRAMP falls back to its classical implementation.
Furthermore, this approach has the following limitations:
ssh-agent
, using public key authentication, or
using ControlMaster options.
interrupt-process
.
process-tty-name
.
remote-pid
.
In order to gain even more performance, it is recommended to bind
tramp-verbose
to 0 when running make-process
or
start-file-process
. Furthermore, you might set
tramp-use-connection-share
to nil
in order to bypass
TRAMP’s handling of the ControlMaster options, and
use your own settings in ~/.ssh/config, see Using ssh connection sharing.
Note: In previous TRAMP versions this was triggered
by the connection property "direct-async-process"
. This is still
supported but deprecated, and it will be removed in a future
TRAMP version.
TRAMP provides several ways to flush remote connections.
This command flushes all connection related objects. vec is the internal representation of a remote connection. When called interactively, this command lists active remote connections in the minibuffer. Each connection is of the format /method:user@host:.
Flushing remote connections also cleans the password cache (see Reusing passwords for several connections), file cache, connection cache (see Reusing connection related information), and recentf cache. It also deletes session timers (see Setting own connection related information) and connection buffers.
If keep-debug is non-nil
, the debug buffer is kept. A
non-nil
keep-password preserves the password cache.
Flushes the current buffer’s remote connection objects, the same as in
tramp-cleanup-connection
.
Flushes all active remote connection objects, the same as in
tramp-cleanup-connection
. This command removes also ad-hoc
proxy definitions (see Declaring multiple hops in the file name).
Just as for tramp-cleanup-all-connections
, all remote
connections and ad-hoc proxy definition are cleaned up in addition to
killing all buffers related to remote connections.
Similar to tramp-cleanup-all-buffers
, where all remote
connections and ad-hoc proxy definition are cleaned up. However,
additional buffers are killed only if one of the functions in
tramp-cleanup-some-buffers-hook
returns t
.
The functions in this hook determine, whether a remote buffer is
killed when tramp-cleanup-some-buffers
is called. Per default,
remote buffers which are linked to a remote file, remote dired
buffers, and buffers related to a remote process are cleaned up.
Sometimes, it is desirable to safe file contents of buffers visiting a given remote host. This could happen for example, if the local host changes its network integration, and the remote host is not reachable anymore.
Replace in all buffers the visiting file name from source to target. source is a remote directory name, which could contain also a localname part. target is the directory name source is replaced with. Often, target is a remote directory name on another host, but it can also be a local directory name. If target has no local part, the local part from source is used.
If target is nil
, it is selected according to the first
match in tramp-default-rename-alist
. If called interactively,
this match is offered as initial value for selection.
On all buffers, which have a buffer-file-name
matching
source, this name is modified by replacing source with
target. This is applied by calling
set-visited-file-name
. The new buffer-file-name
is
prompted for modification in the minibuffer. The buffers are marked
modified, and must be saved explicitly.
If user option tramp-confirm-rename-file-names
is nil
,
changing the file name happens without confirmation. This requires a
matching entry in tramp-default-rename-alist
.
Remote buffers related to the remote connection identified by source, which are not visiting files, or which are visiting files not matching source, are not modified.
Interactively, target is selected from
tramp-default-rename-alist
without confirmation if the prefix
argument is non-nil
.
The remote connection identified by source is flushed by
tramp-cleanup-connection
.
Replace visiting file names to target. The current buffer must be related to a remote connection. In all buffers, which are visiting a file with the same directory name, the buffer file name is changed.
Interactively, target is selected from
tramp-default-rename-alist
without confirmation if the prefix
argument is non-nil
.
The default target for renaming remote buffer file names. This is an
alist of cons cells (source . target)
. The first matching item
specifies the target to be applied for renaming buffer file names from
source via tramp-rename-files
. source
is a regular
expressions, which matches a remote file name. target
must be
a directory name, which could be remote (including remote directories
TRAMP infers by default, such as /method:user@host:).
target
can contain the patterns %m
, %u
or
%h
, which are replaced by the method name, user name or host
name of source
when calling tramp-rename-files
.
source
could also be a Lisp form, which will be evaluated. The
result must be a string or nil
, which is interpreted as a
regular expression which always matches.
Example entries:
("/ssh:badhost:/path/to/dir/" . "/ssh:goodhost:/path/to/another/dir/")
would trigger renaming of buffer file names on ‘badhost’ to ‘goodhost’, including changing the directory name.
("/ssh:.+\\.company\\.org:" . "/ssh:multi.hop|ssh:%h:")
routes all connections to a host in ‘company.org’ via /ssh:multi.hop:, which might be useful when using Emacs outside the company network.
(nil . "~/saved-files/%m:%u@%h/")
saves all remote files locally, with a directory name including method name, user name and host name of the remote connection.
Whether renaming a buffer file name by tramp-rename-files
or
tramp-rename-these-files
must be confirmed.
TRAMP offers also transparent access to files inside file archives. This is possible only on hosts which have installed GVFS (the GNOME Virtual File System), see GVFS-based external methods. Internally, file archives are mounted via the GVFS archive method.
A file archive is a regular file of kind /path/to/dir/file.EXT. The extension ‘.EXT’ identifies the type of the file archive. To examine the contents of an archive with Dired, open file name as if it were a directory (i.e., open /path/to/dir/file.EXT/). A file inside a file archive, called archive file name, has the name /path/to/dir/file.EXT/dir/file.
Most of the magic file name operations, are implemented for archive file names, exceptions are all operations which write into a file archive, and process related operations. Therefore, functions like
(copy-file "/path/to/dir/file.tar/dir/file" "/somewhere/else")
work out of the box. This is also true for file name completion, and
for libraries like dired
or ediff
, which accept archive
file names as well.
File archives are identified by the file name extension ‘.EXT’.
Since GVFS uses internally the library libarchive(3)
,
all suffixes, which are accepted by this library, work also for
archive file names. Accepted suffixes are listed in the constant
tramp-archive-suffixes
. They are
File archives could also be compressed, identified by an additional
compression suffix. Valid compression suffixes are listed in the
constant tramp-archive-compression-suffixes
. They are
‘.bz2’, ‘.gz’, ‘.lrz’, ‘.lz’, ‘.lz4’,
‘.lzma’, ‘.lzo’, ‘.uu’, ‘.xz’, ‘.Z’, and
‘.zst’. A valid archive file name would be
/path/to/dir/file.tar.gz/dir/file. Even several suffixes in a
row are possible, like /path/to/dir/file.tar.gz.uu/dir/file.
An archive file name could be a remote file name, as in
/ftp:anonymous@ftp.gnu.org:/gnu/tramp/tramp-2.4.5.tar.gz/INSTALL.
Since all file operations are mapped internally to GVFS
operations, remote file names supported by tramp-gvfs
perform
better, because no local copy of the file archive must be downloaded
first. For example, ‘/sftp:user@host:...’ performs better than
the similar ‘/scp:user@host:...’. See the constant
tramp-archive-all-gvfs-methods
for a complete list of
tramp-gvfs
supported method names.
If url-handler-mode
is enabled, archives could be visited via
URLs, like
https://ftp.gnu.org/gnu/tramp/tramp-2.4.5.tar.gz/INSTALL. This
allows complex file operations like
(progn (url-handler-mode 1) (ediff-directories "https://ftp.gnu.org/gnu/tramp/tramp-2.4.4.tar.gz/tramp-2.4.4" "https://ftp.gnu.org/gnu/tramp/tramp-2.4.5.tar.gz/tramp-2.4.5" ""))
It is even possible to access file archives in file archives, as
(progn (url-handler-mode 1) (find-file "https://ftp.debian.org/debian/pool/main/c/coreutils/\ coreutils_8.28-1_amd64.deb/control.tar.gz/control"))
In order to disable file archives, you could add the following form to your init file:
(customize-set-variable 'tramp-archive-enabled nil)
TRAMP’s development team is actively engaged in solving bugs and problems and looks to feature requests and suggestions.
TRAMP’s mailing list is the place for more advice and information on working with TRAMP, solving problems, discussing, and general discussions about TRAMP.
TRAMP’s mailing list is moderated but even non-subscribers can post for moderator approval. Sometimes this approval step may take as long as 48 hours due to public holidays.
tramp-devel@gnu.org is the mailing list. Messages sent to this address go to all the subscribers. This is not the address to send subscription requests to.
To subscribe to the mailing list, visit: the TRAMP Mail Subscription Page.
There is also a Gmane group, mirroring the mailing list. Its name is ‘gmane.emacs.tramp’.
Before sending a bug report, run the test suite first A test suite for TRAMP.
Check if the bug or problem is already addressed in See Frequently Asked Questions.
Run M-x tramp-bug RET to generate a buffer with details of the system along with the details of the TRAMP installation. Please include these details with the bug report.
The bug report must describe in as excruciating detail as possible the steps required to reproduce the problem. These details must include the setup of the remote host and any special or unique conditions that exist.
Include a minimal test case that reproduces the problem. This will help the development team find the best solution and avoid unrelated detours.
To exclude cache-related problems, flush all caches before running the
test, see Cleanup remote connections. Alternatively, and often
better for analysis, reproduce the problem in a clean Emacs session
started with emacs -Q
. Then, TRAMP does not load
the persistency file (see Reusing connection related information), and it does not use
passwords from auth-source.el (see Reusing passwords for several connections). The
latter does not happen for the sudoedit method, otherwise it
would be unusable.
If you use the GNU ELPA version of TRAMP, you must load it
explicitly, because emacs -Q
ignores installed ELPA
packages. Call (version number adapted)
$ emacs -Q -l ~/.emacs.d/elpa/tramp-2.4.5.1/tramp-autoloads
When including TRAMP’s messages in the bug report, increase the verbosity level to 6 (see Traces) in the ~/.emacs file before repeating steps to the bug. Include the contents of the *tramp/foo* and *debug tramp/foo* buffers with the bug report. Both buffers could contain non-ASCII characters which are relevant for analysis, append the buffers as attachments to the bug report. This is also needed in order to avoid line breaks during mail transfer.
If you send the message from Emacs, you are asked about to append these buffers to the bug report. If you use an external mail program, you must save these buffers to files, and append them with that mail program.
Note that a verbosity level greater than 6 is not necessary at this stage. Also note that a verbosity level of 6 or greater, the contents of files and directories will be included in the debug buffer. Passwords typed in TRAMP will never be included there.
The official name is “Tramp”. This is used in comments, docstrings, and everywhere speaking about TRAMP.
However, for historical reasons this is formatted as “@sc{Tramp}” in the TRAMP manual. So it looks different there.
TRAMP is available at the GNU URL:
https://ftp.gnu.org/gnu/tramp/
TRAMP’s GNU project page is located here:
The package works successfully on Emacs 27, Emacs 28, Emacs 29, and Emacs 30.
While Unix and Unix-like systems are the primary remote targets, TRAMP has equal success connecting to other platforms, such as MS Windows 7/8/10.
TRAMP does many things in the background, some of which depends on network speeds, response speeds of remote hosts, and authentication delays. During these operations, TRAMP’s responsiveness slows down. Some suggestions within the scope of TRAMP’s settings include:
tramp-persistency-file-name
, which is where
TRAMP caches remote information about hosts and files. Caching
is enabled by default. Don’t disable it.
Set remote-file-name-inhibit-cache
to nil
if remote
files are not independently updated outside TRAMP’s control.
That cache cleanup will be necessary if the remote directories or
files are updated independent of TRAMP.
(setq vc-ignore-dir-regexp (format "\\(%s\\)\\|\\(%s\\)" vc-ignore-dir-regexp tramp-file-name-regexp))
If this is too radical, because you want to use version control
remotely, trim vc-handled-backends
to just those you care
about, for example:
(setq vc-handled-backends '(SVN Git))
remote-file-name-inhibit-locks
to
t
if you know that different Emacs sessions are not modifying
the same remote file.
remote-file-name-inhibit-auto-save
to
t
, but think about the consequences!
If you want to disable auto-saving just for selected connections, for
example due to security considerations, use connection-local variables
in order to set buffer-auto-save-file-name
. If you, for
example, want to disable auto-saving for all sudo
connections, apply the following code.
(connection-local-set-profile-variables 'my-auto-save-profile '((buffer-auto-save-file-name . nil)))
(connection-local-set-profiles '(:application tramp :protocol "sudo") 'my-auto-save-profile)
shell
. Set
shell-history-file-name
to t
.
tramp-verbose
to 3 or lower,
default being 3. Increase trace levels temporarily when hunting for
bugs.
Three main reasons for why TRAMP does not connect to the remote host:
TRAMP needs a clean recognizable prompt on the remote host for accurate parsing. Shell prompts that contain escape sequences for coloring cause parsing problems. Remote shell setup hints for customizing prompt detection using regular expressions.
To check if the remote host’s prompt is being recognized, use this test: switch to TRAMP connection buffer *tramp/foo*, put the cursor at the top of the buffer, and then apply the following expression:
M-: (re-search-forward (concat tramp-shell-prompt-pattern "$")) RET
If the cursor has not moved to the prompt at the bottom of the buffer, then TRAMP has failed to recognize the prompt.
When using zsh on remote hosts, disable zsh line editor because zsh uses left-hand side and right-hand side prompts in parallel. Add the following line to ~/.zshrc:
[[ $TERM == "dumb" ]] && unsetopt zle && PS1='$ ' && return
This uses the default value of tramp-terminal-type
, "dumb"
,
as value of the TERM
environment variable. If you want to use
another value for TERM
, change tramp-terminal-type
and
this line accordingly.
Alternatively, you could set the remote login shell explicitly. See Remote shell setup hints for discussion of this technique,
When using fish shell on remote hosts, disable fancy formatting by adding the following to ~/.config/fish/config.fish:
function fish_prompt if test $TERM = "dumb" echo "\$ " else ... end end
When using WinSSHD on remote hosts, TRAMP does not recognize the strange prompt settings.
A similar problem exist with the iTerm2 shell integration, which sends proprietary escape codes when starting a shell. This can be suppressed by changing the respective integration snippet in your ~/.profile like this:
[ $TERM = "dumb" ] || \ test -e "${HOME}/.iterm2_shell_integration.bash" && \ source "${HOME}/.iterm2_shell_integration.bash"
And finally, bash’s readline should not use key bindings like ‘C-j’ to commands. Disable this in your ~/.inputrc:
$if term=dumb
# Don't bind Control-J or it messes up TRAMP.
$else
"\C-j": next-history
$endif
TRAMP suppresses echos from remote hosts with the
stty -echo
command. But sometimes it is too late to suppress
welcome messages from the remote host containing harmful control
characters. Using sshx or scpx methods can avoid
this problem because they allocate a pseudo tty. See Inline methods.
Set tramp-chunksize
to 500 to get around this problem, which is
related to faulty implementation of process-send-string
on
HP-UX, FreeBSD and Tru64 Unix systems. Consult the documentation for
tramp-chunksize
to see when this is necessary.
Set file-precious-flag
to t
for files accessed by
TRAMP so the file contents are checked using checksum by
first saving to a temporary file.
(add-hook 'find-file-hook (lambda () (when (file-remote-p default-directory) (set (make-local-variable 'file-precious-flag) t))))
When connecting to a local host, TRAMP uses some internal
optimizations. They fail when Emacs runs in a chrooted environment.
In order to disable those optimizations, set user option
tramp-local-host-regexp
to nil
.
Some packages, like desktop.el or recentf.el, access
remote files when loaded. If the requested file is not accessible,
TRAMP could block. In order to check whether this could
happen, add a test via access-file
with a proper timeout prior
to loading these packages:
(let ((remote-file-name-access-timeout 10)) (access-file "/method:user@host:/path/to/file" "error")) ⇒ nil
The result nil
means success. If the file is not accessible,
or if the underlying operations last too long, access-file
returns with an error.
The value of the timeout (10 seconds in the example) depends on your preference and on the quality of the connection to the remote host. If the connection to the remote host isn’t established yet, and if this requires an interactive password, the timeout check doesn’t work properly.
Note: In recent versions of Emacs, both packages already
apply this check. You just need to customize
remote-file-name-access-timeout
to the desired timeout (in
seconds).
Yes. OpenSSH
has added support for FIDO hardware
devices via special key types *-sk. TRAMP supports
the additional handshaking messages for them. This requires at least
OpenSSH
8.2, and a FIDO U2F or
FIDO2 compatible security key, like yubikey, solokey,
nitrokey, or titankey.
Note that there are reports on problems of handling FIDO2
(residential) keys by ssh-agent
. As workaround, you might
disable ssh-agent
for such keys.
Recent versions of smbclient
do not support old connection
protocols by default. In order to connect to such a host, add a
respective option:
(add-to-list 'tramp-smb-options "client min protocol=NT1")
Note that using a deprecated connection protocol raises security problems, you should do it only if absolutely necessary.
ANSI escape sequences from the remote shell may cause errors in TRAMP’s parsing of remote buffers.
To test if this is the case, open a remote shell and check if the output
of ls
is in color.
To disable ANSI escape sequences from the remote hosts, disable ‘--color=yes’ or ‘--color=auto’ in the remote host’s .bashrc or .profile. Turn this alias on and off to see if file name completion works.
This may be related to globbing, which is the use of shell’s ability to expand wild card specifications, such as ‘*.c’. For directories with large number of files, globbing might exceed the shell’s limit on length of command lines and hang. TRAMP uses globbing.
To test if globbing hangs, open a shell on the remote host and then
run ls -d * ..?* > /dev/null
.
When testing, ensure the remote shell is the same shell
(/bin/sh
, ksh
or bash
), that
TRAMP uses when connecting to that host.
Make Emacs beep after reading from or writing to the remote host with the following code in ~/.emacs.
(add-hook 'tramp-handle-write-region-hook 'beep) (add-hook 'tramp-handle-file-local-copy-hook 'beep)
Install tramp-theme from GNU ELPA via Emacs’s Package Manager.
Enable it via M-x load-theme RET tramp RET. Further
customization is explained in user option
tramp-theme-face-remapping-alist
.
Emacs computes the dired
options based on the local host.
Since Emacs 30, these options can be set connection-local.
(connection-local-set-profile-variables 'my-dired-profile '((dired-listing-switches . "-ahl")))
(connection-local-set-profiles '(:application tramp :machine "remotehost") 'my-dired-profile)
In older Emacsen, you can set the dired
options with a hook
as follows:
(add-hook 'dired-before-readin-hook (lambda () (when (string-equal (file-remote-p default-directory 'host) "remotehost") (setq dired-actual-switches "-ahl"))))
Internally, TRAMP uses commands like ls
or
stat
in order to determine file permissions. When
NFS4_ACL is enabled on the remote host, more fine-grained
information is used which cannot be reflected by the permission string
returned from those commands. Set the user option
tramp-use-file-attributes
to nil
in such a case. This
can also be set host-wise, like in:
(connection-local-set-profile-variables 'my-file-attributes-profile '((tramp-use-file-attributes . nil)))
(connection-local-set-profiles '(:application tramp :machine "remotehost") 'my-file-attributes-profile)
Emacs can trash files instead of deleting
them.
Remote files are always trashed to the local trash, except the user
option remote-file-name-inhibit-delete-by-moving-to-trash
is
non-nil
, or it is a remote encrypted file (see Protect remote files by encryption), which are deleted anyway.
If you want to trash a remote file into a remote trash directory, you
could configure the user option trash-directory
to a
connection-local value.
(connection-local-set-profile-variables 'remote-trash-directory '((trash-directory . "/sudo::~/.local/share/Trash")))
(connection-local-set-profiles `(:application tramp :protocol "sudo" :machine ,system-name) 'remote-trash-directory)
If Emacs is configured to use the XDG conventions for the trash directory, remote files cannot be restored with the respective tools, because those conventions don’t specify remote paths. Such files must be restored by moving them manually from ${XDG_DATA_HOME}/Trash/files/, if needed.
Adapt several of these approaches to reduce typing. If the full name is /ssh:news@news.my.domain:/opt/news/etc, then:
If you always apply the default method (see Selecting a default method), you could use the simplified TRAMP syntax (see Alternative file name syntax):
(customize-set-variable 'tramp-default-method "ssh") (tramp-change-syntax 'simplified)
The reduced typing: C-x C-f
/news@news.my.domain:/opt/news/etc
RET.
You can define default methods and user names for hosts, (see Selecting a default method, see Selecting a default user):
(custom-set-variables '(tramp-default-method "ssh") '(tramp-default-user "news"))
The reduced typing: C-x C-f /-:news.my.domain:/opt/news/etc RET.
Note that there are some useful shortcuts already. Accessing your local host as ‘root’ user, is possible just by C-x C-f /su:: RET.
Programs used for access methods already offer powerful configurations (see Selecting config files for user/host name completion). For ssh, configure the file ~/.ssh/config:
Host xy HostName news.my.domain User news
The reduced typing: C-x C-f /ssh:xy:/opt/news/etc RET.
Depending on the number of files in the directories, host names completion can further reduce key strokes: C-x C-f /ssh:x TAB.
For long file names, set up environment variables that are expanded in the minibuffer. Environment variables are set either outside Emacs or inside Emacs with Lisp:
(setenv "xy" "/ssh:news@news.my.domain:/opt/news/etc/")
The reduced typing: C-x C-f $xy RET.
Note that file name cannot be edited here because the environment variables are not expanded during editing in the minibuffer.
Redefine another key sequence in Emacs for C-x C-f:
(global-set-key
[(control x) (control y)]
(lambda ()
(interactive)
(find-file
(read-file-name
"Find TRAMP file: "
"/ssh:news@news.my.domain:/opt/news/etc/"))))
Simply typing C-x C-y would prepare minibuffer editing of file name.
See the Emacs Wiki for a more comprehensive example.
Abbreviation list expansion can be used to reduce typing long file names:
(add-to-list 'directory-abbrev-alist '("^/xy" . "/ssh:news@news.my.domain:/opt/news/etc/"))
The reduced typing: C-x C-f /xy RET.
Note that file name cannot be edited here because the abbreviations are not expanded during editing in the minibuffer. Furthermore, the abbreviation is not expanded during TAB completion.
The abbrev-mode
gives additional flexibility for editing in the
minibuffer:
(define-abbrev-table 'my-tramp-abbrev-table '(("xy" "/ssh:news@news.my.domain:/opt/news/etc/")))
(add-hook 'minibuffer-setup-hook (lambda () (abbrev-mode 1) (setq local-abbrev-table my-tramp-abbrev-table)))
(advice-add 'minibuffer-complete :before 'expand-abbrev)
The reduced typing: C-x C-f xy TAB.
The minibuffer expands for further editing.
Use bookmarks to save TRAMP file names.
Upon visiting a location with TRAMP, save it as a bookmark with menu-bar edit bookmarks set.
To revisit that bookmark: menu-bar edit bookmarks jump.
recentf remembers visited places.
Keep remote file names in the recent list without have to check for their accessibility through remote access:
(recentf-mode 1)
Reaching recently opened files: menu-bar file Open Recent.
Since filecache remembers visited places, add the remote directory to the cache:
(with-eval-after-load 'filecache (file-cache-add-directory "/ssh:news@news.my.domain:/opt/news/etc/"))
Then use directory completion in the minibuffer with C-x C-f C-TAB.
bbdb has a built-in feature for Ange FTP files, which also works for TRAMP file names.
Load bbdb in Emacs:
(require 'bbdb) (bbdb-initialize)
Create a BBDB entry with M-x bbdb-create-ftp-site RET. Then specify a method and user name where needed. Examples:
M-x bbdb-create-ftp-site RET Ftp Site: news.my.domain RET Ftp Directory: /opt/news/etc/ RET Ftp Username: ssh:news RET Company: RET Additional Comments: RET
In BBDB buffer, access an entry by pressing the key F.
Thanks to TRAMP users for contributing to these recipes.
When saving ad-hoc multi-hop TRAMP file names (see Declaring multiple hops in the file name) via bookmarks, recent files, filecache, bbdb, or another package, use the full ad-hoc file name including all hops, like /ssh:bird@bastion|ssh:news.my.domain:/opt/news/etc.
Alternatively, when saving abbreviated multi-hop file names
/ssh:news@news.my.domain:/opt/news/etc, the user
option tramp-save-ad-hoc-proxies
must be set non-nil
value.
Configure Emacs Client
Then on the remote host, start the Emacs Server:
(require 'server) (setq server-host (system-name) server-use-tcp t) (server-start)
If (system-name)
of the remote host cannot be resolved on the
local host, use IP address instead.
Copy from the remote host the resulting file ~/.emacs.d/server/server to the local host, to the same location.
Then start Emacs Client from the command line:
$ emacsclient /ssh:user@host:/file/to/edit
user
and host
refer to the local host.
To make Emacs Client an editor for other programs, use a wrapper script emacsclient.sh:
#!/bin/sh emacsclient /ssh:$(whoami)@$(hostname --fqdn):$1
Then change the environment variable EDITOR
to point to the
wrapper script:
$ export EDITOR=/path/to/emacsclient.sh
The buffer-local variable default-directory
tells this. If the
form (file-remote-p default-directory)
returns non-nil
,
the buffer is remote. See the optional arguments of
file-remote-p
for determining details of the remote connection.
If the local machine Emacs is running on changes its network integration, remote hosts could become unreachable. This happens for example, if the local machine is moved between your office and your home without restarting Emacs.
In such cases, the command tramp-rename-files
can be used to
alter remote buffers’ method, host, and/or directory names. This
permits saving their contents in the same location via another network
path, or somewhere else entirely (including locally). see Renaming remote files.
recentf-list
?
When TRAMP cleans a connection, it removes the respective
remote file name(s) from recentf-list
. This is needed, because
an unresponsive remote host could trigger recentf
to connect
that host again and again.
If you find the cleanup disturbing, because the file names in
recentf-list
are precious to you, you could add the following
two forms in your ~/.emacs after loading the tramp
and
recentf
packages:
(remove-hook 'tramp-cleanup-connection-hook #'tramp-recentf-cleanup)
(remove-hook 'tramp-cleanup-all-connections-hook #'tramp-recentf-cleanup-all)
TRAMP comes with compatibility code for different Emacs versions. When you see such a message (the text might differ), you don’t use the Emacs built-in version of TRAMP, and you must recompile it. In case you have installed TRAMP from GNU ELPA, See Installing TRAMP via GNU ELPA. Otherwise, See Recompilation when the Emacs version has changed.
Timers, process filters and sentinels, and other event based functions can run at any time, when a remote file operation is still running. This can cause TRAMP to block. When such a situation is detected, this error is triggered. It should be fixed in the respective function (sending an error report will help), but for the time being you can suppress this error by the following code in your ~/.emacs:
(setq debug-ignored-errors (cons 'remote-file-error debug-ignored-errors))
TRAMP has changed the signature of an internal function. External packages implementing an own TRAMP backend must follow this change. Please report this problem to the author of that package.
For the running session, TRAMP disables the external package, and you can continue to work. If you don’t want to see this error while activating TRAMP, you can suppress it by the same code as above in your ~/.emacs:
(setq debug-ignored-errors (cons 'remote-file-error debug-ignored-errors))
Sometimes, for example while saving remote files, errors appear when
changing file attributes like permissions, time stamps, or ownership.
If these errors can be ignored, set user option
tramp-inhibit-errors-if-setting-file-attributes-fail
to a
non-nil
value. This transforms the error into a warning.
Sometimes, for example while saving remote files, errors appear when
changing file attributes like permissions, time stamps, or ownership.
If these errors can be ignored, set user option
tramp-inhibit-errors-if-setting-file-attributes-fail
to a
non-nil
value. This transforms the error into a warning.
There are packages that call TRAMP without the user ever entering a remote file name. Even without applying a remote file syntax, some packages enable TRAMP on their own. How can users disable such features.
Disable TRAMP file name completion:
(customize-set-variable 'ido-enable-tramp-completion nil)
Disable remote directory tracking mode:
(rlogin-directory-tracking-mode -1)
(customize-set-variable 'tramp-default-method "ftp")
If you want to enable Ange FTP’s syntax, add the following form:
(tramp-change-syntax 'simplified)
tramp-ignored-file-name-regexp
to a proper regexp in
.emacs. Note, that we don’t use
customize-set-variable
, in order to avoid loading
TRAMP.
(setq tramp-ignored-file-name-regexp "\\`/ssh:example\\.com:")
This is needed, if you mount for example a virtual file system on your local host’s root directory as /ssh:example.com:.
(inhibit-remote-files)
without-remote-files
macro.
(without-remote-files ...)
This improves performance, because many primitive file name operations don’t check any longer for TRAMP file name regexps then.
The difference is that Ange FTP uses ftp
to transfer files
between the local and the remote host, whereas TRAMP uses a
combination of ssh
and scp
or other work-alike
programs.
Internally, TRAMP uses "~/.cache/emacs"
as local temporary directory if it exists. Otherwise, the value of
temporary-file-directory
is used, which is often "/tmp"
.
This local temporary directory is kept in the constant
tramp-compat-temporary-file-directory
. In this manual, we use
"<TMP>"
for its value.
The temporary directory on a remote host is "/data/local/tmp"
for
the adb method, "/C$/Temp"
for the smb method,
and "/tmp"
otherwise. For some methods, this can be customized.
Temporary files have the file name prefix "tramp."
. If you want
to change this prefix, for example because you want to identify
temporary files produced by file-local-copy
in your package,
you can bind the variable tramp-temp-name-prefix
temporarily:
(let ((tramp-temp-name-prefix "my-prefix.")) (file-local-copy "/ssh::.emacs")) ⇒ "/tmp/my-prefix.HDfgDZ"
TRAMP package redefines lisp functions
file-name-directory
and file-name-nondirectory
to
accommodate the unique file naming syntax that TRAMP requires.
The replacements dissect the file name, use the original handler for the localname, take that result, and then re-build the TRAMP file name. By relying on the original handlers for localnames, TRAMP benefits from platform specific hacks to the original handlers.
In general, it is not recommended to use TRAMP functions and variables not described in this manual. They might change their signature and/or semantics without any announcement.
Sometimes, it is not convenient to open a new connection to a remote
host, including entering the password and alike. For example, this is
nasty for packages providing file name completion. Such a package
could signal to TRAMP, that they don’t want it to establish a
new connection. Use the variable non-essential
temporarily and
bind it to non-nil
value.
(let ((non-essential t)) ...)
Keeping a local cache of remote file attributes in sync with the remote host is a time-consuming operation. Flushing and re-querying these attributes can tax TRAMP to a grinding halt on busy remote hosts.
To get around these types of slow-downs in TRAMP’s
responsiveness, set the process-file-side-effects
to nil
to stop TRAMP from flushing the cache. This is helpful in
situations where callers to process-file
know there are no file
attribute changes. The let-bind form to accomplish this:
(let (process-file-side-effects) ...)
For asynchronous processes, TRAMP uses a process sentinel to
flush file attributes cache. When callers to start-file-process
know beforehand no file attribute changes are expected, then the
process sentinel should be set to the default state. In cases where
the caller defines its own process sentinel, TRAMP’s process
sentinel is overwritten. The caller can still flush the file
attributes cache in its process sentinel with this code:
(unless (memq (process-status proc) '(run open)) (dired-uncache remote-directory))
Since TRAMP traverses subdirectories starting with the
root directory, it is most likely sufficient to make the
default-directory
of the process buffer as the root directory.
Timers run asynchronously at any time when Emacs is waiting for
sending a string to a process, or waiting for process output. They
can run any remote file operation, which would conflict with the
already running remote file operation, if the same connection is
affected. TRAMP detects this situation, and raises the
remote-file-error
error. A timer function should avoid this
situation. As a minimum, it should protect itself against this error, by
wrapping the timer function body as follows:
(ignore-error 'remote-file-error ...)
TRAMP messages are raised with verbosity levels ranging from 0
to 10. TRAMP does not display all messages; only those with a
verbosity level less than or equal to tramp-verbose
.
The verbosity levels are
With tramp-verbose
greater than or equal to 4, messages are
also written to the TRAMP debug buffer *debug
tramp/foo*. Such debug buffers are essential to bug and problem
analyzes. For TRAMP bug reports, set the tramp-verbose
level to 6 (see Reporting Bugs and Problems).
The debug buffer is in Outline Mode. In this buffer, messages can be filtered by their level. To see messages up to verbosity level 5, enter C-u 6 C-c C-q.
TRAMP handles errors internally. Hence, to get a Lisp backtrace, the following settings are required:
(setq debug-on-error t debug-on-signal t)
If tramp-verbose
is greater than or equal to 10, Lisp
backtraces are also added to the TRAMP debug buffer in case of
errors.
In very rare cases it could happen, that TRAMP blocks Emacs. Killing Emacs does not allow inspecting the debug buffer. In that case, you can instruct TRAMP to mirror the debug buffer to a file:
(customize-set-variable 'tramp-debug-to-file t)
The debug buffer is written as a file in your Where temporary files are kept. Use this option with care, because it could decrease the performance of TRAMP actions.
If tramp-verbose
is greater than or equal to 11, TRAMP
function call traces are written to the buffer *trace tramp/foo*.
When tramp-debug-command-messages
is non-nil
, the debug
buffer contains all messages with verbosity level 6 (sent and received
strings), and the entry and exit messages for the function
tramp-file-name-handler
. This is intended for TRAMP
maintainers, analyzing the remote commands for performance analysis.
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Where temporary files are kept
This shouldn’t be needed with recent OpenSSH
versions for MS Windows. Use method sshx.
On the local
host, run0
uses a graphical password agent.