Update to reflect recent changes to coreutils.texi.

This commit is contained in:
Paul Eggert 2006-07-23 01:27:27 +00:00
parent bdcc26e24b
commit 7192610528
2 changed files with 52 additions and 36 deletions

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@ -1,3 +1,7 @@
2006-07-22 Paul Eggert <eggert@cs.ucla.edu>
* man/chmod.x: Update to reflect recent changes to coreutils.texi.
2006-07-21 Jim Meyering <jim@meyering.net>
* src/su.c (usage): Correct typo in --help output: s/commmand/command/

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[NAME]
chmod \- change file access permissions
chmod \- change file mode bits
[DESCRIPTION]
This manual page
documents the GNU version of
.BR chmod .
.B chmod
changes the permissions of each given file according to
changes the file mode bits of each given file according to
.IR mode ,
which can be either a symbolic representation of changes to make, or
an octal number representing the bit pattern for the new permissions.
an octal number representing the bit pattern for the new mode bits.
.PP
The format of a symbolic mode is
`[ugoa...][[+-=][rwxXstugo...]...][,...]'. Multiple symbolic
operations can be given, separated by commas.
The format of a symbolic mode is [\c
\fBugoa\fP.\|.\|.][[\fB+-=\fP][\fIperms\fP.\|.\|.].\|.\|.],
where
.I "perms"
is either zero or more letters from the set
\fBrwxXst\fP, or a single letter from the set \fBugo\fP.
Multiple symbolic
modes can be given, separated by commas.
.PP
A combination of the letters `ugoa' controls which users' access to
the file will be changed: the user who owns it (u), other users in the
file's group (g), other users not in the file's group (o), or all
users (a). If none of these are given, the effect is as if `a' were
A combination of the letters \fBugoa\fP controls which users' access
to the file will be changed: the user who owns it (\fBu\fP), other
users in the file's group (\fBg\fP), other users not in the file's
group (\fBo\fP), or all users (\fBa\fP). If none of these are given,
the effect is as if \fBa\fP were
given, but bits that are set in the umask are not affected.
.PP
The operator `+' causes the permissions selected to be added to the
existing permissions of each file; `-' causes them to be removed; and
`=' causes them to be the only permissions that the file has.
The operator \fB+\fP causes the selected file mode bits to be added to
the existing file mode bits of each file; \fB-\fP causes them to be
removed; and \fB=\fP causes them to be added and causes unmentioned
bits to be removed except that a directory's unmentioned set user and
group ID bits are not affected.
.PP
The letters `rwxXstugo' select the new permissions for the affected
users: read (r), write (w), execute (or access for directories) (x),
execute only if the file is a directory or already has execute
permission for some user (X), set user or group ID on execution (s),
sticky (t), the permissions granted to the user who owns the file (u),
the permissions granted to other users who are members of the file's group (g),
The letters \fBrwxXst\fP select file mode bits for the affected users:
read (\fBr\fP), write (\fBw\fP), execute (or search for directories)
(\fBx\fP), execute/search only if the file is a directory or already
has execute permission for some user (\fBX\fP), set user or group ID
on execution (\fBs\fP), restricted deletion flag or sticky bit
(\fBt\fP). Instead of one or more of these letters, you can specify
exactly one of the letters \fBugo\fP: the permissions granted to the
user who owns the file (\fBu\fP), the permissions granted to other
users who are members of the file's group (\fBg\fP),
and the permissions granted to users that are in neither of the two preceding
categories (o).
categories (\fBo\fP).
.PP
A numeric mode is from one to four octal digits (0-7), derived by
adding up the bits with values 4, 2, and 1. Any omitted digits are
assumed to be leading zeros. The first digit selects the set user ID
(4) and set group ID (2) and sticky (1) attributes. The second digit
A numeric mode is from one to four octal digits (0\-7), derived by
adding up the bits with values 4, 2, and 1. Omitted digits are
assumed to be leading zeros, except that if the first digit is
omitted, a directory's set user and group ID bits are not affected.
The first digit selects the set user ID (4) and set group ID (2) and
restricted deletion or sticky (1) attributes. The second digit
selects permissions for the user who owns the file: read (4), write (2),
and execute (1); the third selects permissions for other users in the
file's group, with the same values; and the fourth for other users not
@ -54,18 +67,17 @@ In contrast,
.B chmod
ignores symbolic links encountered during recursive directory
traversals.
.SH STICKY FILES
On older Unix systems, the sticky bit caused executable files to be
hoarded in swap space. This feature is not useful on modern VM
systems, and the Linux kernel ignores the sticky bit on files. Other
kernels may use the sticky bit on files for system-defined purposes.
On some systems, only the superuser can set the sticky bit on files.
.SH STICKY DIRECTORIES
When the sticky bit is set on a directory, a file in that directory may
be unlinked or renamed only by the directory owner, the file owner, or root.
Without the sticky bit, anyone able to write to the
directory can delete or rename files. The sticky bit is commonly found
on directories, such as /tmp, that are world-writable.
.SH "RESTRICTED DELETION FLAG OR STICKY BIT"
The restricted deletion flag or sticky bit is a single bit, whose
interpretation depends on the file type. For directories, it prevents
unprivileged users from removing or renaming a file in the directory
unless they own the file or the directory; this is called the
.I "restricted deletion flag"
for the directory, and is commonly found on world-writable directories
like \fB/tmp\fP. For regular files on some older systems, the bit
saves the program's text image on the swap device so it will load more
quickly when run; this is called the
.IR "sticky bit" .
.SH OPTIONS
[SEE ALSO]
chmod(2)