Previous: Subprocess Conditions, Up: Subprocesses [Contents][Index]
The following subprocess options may be passed to
run-shell-command or run-synchronous-subprocess. These
options are passed as alternating keyword/value pairs, for example:
(run-shell-command "ls /"
'output my-output-port
'output-buffer-size 8192)
The example shows a shell command being run with two options specified:
output and output-buffer-size.
Specifies the standard input of the subprocess. Port may be an
input port, in which case characters are read from port and fed to
the subprocess until port reaches end-of-file. Alternatively,
port may be #f, indicating that the subprocess has no
standard input.
The default value of this option is #f.
(call-with-input-file "foo.in"
(lambda (port)
(run-shell-command "cat > /dev/null" 'input port)))
Specifies how line-endings should be translated when writing characters
to the subprocess. Ignored if the input option is #f.
Line-ending must be either a string specifying the line ending, or
the symbol default, meaning to use the operating system’s
standard line ending. In either case, newline characters to be written
to the input port are translated to the specified line ending
before being written.
The default value of this option is default.
(call-with-input-file "foo.in"
(lambda (port)
(run-shell-command "cat > /dev/null"
'input port
'input-line-translation "\r\n")))
Specifies the size of the input buffer for the standard input of the
subprocess. (This is the buffer on the Scheme side, and has nothing to
do with any buffering done on the subprocess side.) Ignored if the
input option is #f. N must be an exact positive
integer specifying the number of characters the buffer can hold.
The default value of this option is 512.
(call-with-input-file "foo.in"
(lambda (port)
(run-shell-command "cat > /dev/null"
'input port
'input-buffer-size 4096)))
Specifies the standard output and standard error of the subprocess.
Port may be an output port, in which case characters are read from
the subprocess and fed to port until the subprocess finishes.
Alternatively, port may be #f, indicating that the
subprocess has no standard output or standard error.
The default value of this option is the value of
(current-output-port).
(call-with-output-file "foo.out"
(lambda (port)
(run-shell-command "ls -la /etc" 'output port)))
Specifies how line-endings should be translated when reading characters
from the standard output of the subprocess. Ignored if the
output option is #f. Line-ending must be either a
string specifying the line ending, or the symbol default, meaning
to use the operating system’s standard line ending. In either case,
newline characters read from the subprocess port are translated to the
specified line ending.
The default value of this option is default.
(call-with-output-file "foo.out"
(lambda (port)
(run-shell-command "ls -la /etc"
'output port
'output-line-translation "\r\n")))
Specifies the size of the output buffer for the standard output of the
subprocess. (This is the buffer on the Scheme side, and has nothing to
do with any buffering done on the subprocess side.) Ignored if the
output option is #f. N must be an exact positive
integer specifying the number of characters the buffer can hold.
The default value of this option is 512.
(call-with-output-file "foo.out"
(lambda (port)
(run-shell-command "ls -la /etc"
'output port
'output-buffer-size 4096)))
Specifies that thunk is to be run periodically when output from
the subprocess is available. Thunk must be a procedure of no
arguments, or #f indicating that no hook is supplied. This
option is mostly useful for interactive systems. For example, the Edwin
text editor uses this to update output buffers when running some
subprocesses.
The default value of this option is #f.
(run-shell-command "ls -la /etc"
'redisplay-hook
(lambda ()
(update-buffer-contents buffer)))
Specifies the environment variables that are to be used for the
subprocess. Environment must be either a vector of strings or
#f indicating the default environment. If it is a vector of
strings, each string must be a name/value pair where the name and value
are separated by an equal sign, for example, "foo=bar". To
define a variable with no value, just omit the value, as in "foo=".
Note that the variable scheme-subprocess-environment is bound to
the default subprocess environment.
The default value of this option is #f.
(run-shell-command "ls -la /etc"
'environment
(let* ((v scheme-subprocess-environment)
(n (vector-length v))
(v (vector-grow v (+ n 1))))
(vector-set! v n "TERM=none")
v))
Specifies the working directory in which the subprocess will run.
The default value of this option is (working-directory-pathname).
(run-shell-command "ls -la" 'working-directory "/etc/")
This option is meaningful only on unix systems; on other systems it is ignored. Specifies whether to communicate with the subprocess using PTY devices; if true, PTYs will be used, otherwise pipes will be used.
The default value of this option is #f.
(run-shell-command "ls -la /etc" 'use-pty? #t)
Specifies the shell program to use for run-shell-command.
The default value of this option is (os/shell-file-name). This
is the value of the environment variable SHELL, or if
SHELL is not set, the value is operating-system dependent as
follows:
COMSPEC
is used. If that is not set, cmd.exe is used for Windows NT, or
command.com is used for Windows 9x; in each case the shell is
found by searching the path.
(run-shell-command "ls -la /etc"
'shell-file-name "/usr/local/bin/bash")
Previous: Subprocess Conditions, Up: Subprocesses [Contents][Index]