Deletion means removing part of the text in a buffer, without saving it in the kill ring (see The Kill Ring). Deleted text can’t be yanked, but can be reinserted using the undo mechanism (see Undo). Some deletion functions do save text in the kill ring in some special cases.
All of the deletion functions operate on the current buffer.
This function deletes the entire text of the current buffer
(not just the accessible portion), leaving it
empty. If the buffer is read-only, it signals a buffer-read-only
error; if some of the text in it is read-only, it signals a
text-read-only error. Otherwise, it deletes the text without
asking for any confirmation. It returns nil.
Normally, deleting a large amount of text from a buffer inhibits further
auto-saving of that buffer because it has shrunk. However,
erase-buffer does not do this, the idea being that the future
text is not really related to the former text, and its size should not
be compared with that of the former text.
This command deletes the text between positions start and
end in the current buffer, and returns nil. If point was
inside the deleted region, its value afterward is start.
Otherwise, point relocates with the surrounding text, as markers do.
This function deletes the text between positions start and end in the current buffer, and returns a string containing the text just deleted.
If point was inside the deleted region, its value afterward is start. Otherwise, point relocates with the surrounding text, as markers do.
This command deletes count characters directly after point, or
before point if count is negative. If killp is
non-nil, then it saves the deleted characters in the kill ring.
In an interactive call, count is the numeric prefix argument, and killp is the unprocessed prefix argument. Therefore, if a prefix argument is supplied, the text is saved in the kill ring. If no prefix argument is supplied, then one character is deleted, but not saved in the kill ring.
The value returned is always nil.
This command deletes count characters directly before point, or
after point if count is negative. If killp is
non-nil, then it saves the deleted characters in the kill ring.
In an interactive call, count is the numeric prefix argument, and killp is the unprocessed prefix argument. Therefore, if a prefix argument is supplied, the text is saved in the kill ring. If no prefix argument is supplied, then one character is deleted, but not saved in the kill ring.
The value returned is always nil.
This command deletes count characters backward, changing tabs
into spaces. When the next character to be deleted is a tab, it is
first replaced with the proper number of spaces to preserve alignment
and then one of those spaces is deleted instead of the tab. If
killp is non-nil, then the command saves the deleted
characters in the kill ring.
Conversion of tabs to spaces happens only if count is positive. If it is negative, exactly −count characters after point are deleted.
In an interactive call, count is the numeric prefix argument, and killp is the unprocessed prefix argument. Therefore, if a prefix argument is supplied, the text is saved in the kill ring. If no prefix argument is supplied, then one character is deleted, but not saved in the kill ring.
The value returned is always nil.
This option specifies how backward-delete-char-untabify should
deal with whitespace. Possible values include untabify, the
default, meaning convert a tab to many spaces and delete one;
hungry, meaning delete all tabs and spaces before point with
one command; all meaning delete all tabs, spaces and newlines
before point, and nil, meaning do nothing special for
whitespace characters.