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The functions in this section rename, copy, delete, link, and set the modes of files.
In the functions that have an argument newname, if a file by the name of newname already exists, the actions taken depend on the value of the argument ok-if-already-exists:
file-already-exists error if ok-if-already-exists is
nil.
The next four commands all recursively follow symbolic links at all levels
of parent directories for their first argument, but, if that argument is
itself a symbolic link, then only copy-file replaces it with its
(recursive) target.
This function gives the file named oldname the additional name newname. This means that newname becomes a new “hard link” to oldname.
In the first part of the following example, we list two files, ‘foo’ and ‘foo3’.
% ls -li fo* 81908 -rw-rw-rw- 1 rms 29 Aug 18 20:32 foo 84302 -rw-rw-rw- 1 rms 24 Aug 18 20:31 foo3 |
Now we create a hard link, by calling add-name-to-file, then list the
files again. This shows two names for one file, ‘foo’ and ‘foo2’.
(add-name-to-file "foo" "foo2")
⇒ nil
% ls -li fo*
81908 -rw-rw-rw- 2 rms 29 Aug 18 20:32 foo
81908 -rw-rw-rw- 2 rms 29 Aug 18 20:32 foo2
84302 -rw-rw-rw- 1 rms 24 Aug 18 20:31 foo3
|
Finally, we evaluate the following:
(add-name-to-file "foo" "foo3" t) |
and list the files again. Now there are three names for one file: ‘foo’, ‘foo2’, and ‘foo3’. The old contents of ‘foo3’ are lost.
(add-name-to-file "foo1" "foo3")
⇒ nil
% ls -li fo*
81908 -rw-rw-rw- 3 rms 29 Aug 18 20:32 foo
81908 -rw-rw-rw- 3 rms 29 Aug 18 20:32 foo2
81908 -rw-rw-rw- 3 rms 29 Aug 18 20:32 foo3
|
This function is meaningless on operating systems where multiple names for one file are not allowed. Some systems implement multiple names by copying the file instead.
See also file-nlinks in Other Information about Files.
This command renames the file filename as newname.
If filename has additional names aside from filename, it
continues to have those names. In fact, adding the name newname with
add-name-to-file and then deleting filename has the same effect
as renaming, aside from momentary intermediate states.
This command copies the file oldname to newname. An error is signaled if oldname does not exist. If newname names a directory, it copies oldname into that directory, preserving its final name component.
If time is non-nil, then this function gives the new file the
same last-modified time that the old one has. (This works on only some
operating systems.) If setting the time gets an error, copy-file
signals a file-date-error error. In an interactive call, a prefix
argument specifies a non-nil value for time.
This function copies the file modes, too.
If argument preserve-uid-gid is nil, we let the operating
system decide the user and group ownership of the new file (this is usually
set to the user running Emacs). If preserve-uid-gid is
non-nil, we attempt to copy the user and group ownership of the
file. This works only on some operating systems, and only if you have the
correct permissions to do so.
This command makes a symbolic link to filename, named newname. This is like the shell command ‘ln -s filename newname’.
This function is not available on systems that don't support symbolic links.
This command deletes the file filename, like the shell command ‘rm filename’. If the file has multiple names, it continues to exist under the other names.
A suitable kind of file-error error is signaled if the file does not
exist, or is not deletable. (On Unix and GNU/Linux, a file is deletable if
its directory is writable.)
If filename is a symbolic link, delete-file does not replace it
with its target, but it does follow symbolic links at all levels of parent
directories.
See also delete-directory in Creating and Deleting Directories.
This function defines the logical name varname to have the value string. It is available only on VMS.
This function sets mode bits of filename to mode (which must be an integer). Only the low 12 bits of mode are used. This function recursively follows symbolic links at all levels for filename.
This function sets the default file protection for new files created by
Emacs and its subprocesses. Every file created with Emacs initially has
this protection, or a subset of it (write-region will not give a file
execute permission even if the default file protection allows execute
permission). On Unix and GNU/Linux, the default protection is the bitwise
complement of the “umask” value.
The argument mode must be an integer. On most systems, only the low 9 bits of mode are meaningful. You can use the Lisp construct for octal character codes to enter mode; for example,
(set-default-file-modes ?\644) |
Saving a modified version of an existing file does not count as creating the file; it preserves the existing file's mode, whatever that is. So the default file protection has no effect.
This function returns the current default protection value.
This function sets the access and modification times of filename to
time. The return value is t if the times are successfully set,
otherwise it is nil. time defaults to the current time and
must be in the format returned by current-time (voir la section Time of Day).
On MS-DOS, there is no such thing as an “executable” file mode bit. So
Emacs considers a file executable if its name ends in one of the standard
executable extensions, such as ‘.com’, ‘.bat’, ‘.exe’, and
some others. Files that begin with the Unix-standard ‘#!’ signature,
such as shell and Perl scripts, are also considered as executable files.
This is reflected in the values returned by file-modes and
file-attributes. Directories are also reported with executable bit
set, for compatibility with Unix.
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Ce document a été généré par Eric Reinbold le 13 Octobre 2007 en utilisant texi2html 1.78.