chmod(1) chmod(1)
NAME [Toc] [Back]
chmod - change file mode access permissions
SYNOPSIS [Toc] [Back]
/usr/bin/chmod [-A] [-R] symbolic_mode_list file ...
Obsolescent form:
/usr/bin/chmod [-A] [-R] numeric_mode file ...
DESCRIPTION [Toc] [Back]
The chmod command changes the permissions of one or more files
according to the value of symbolic_mode_list or numeric_mode. You can
display the current permissions for a file with the ls -l command (see
ls(1)).
Symbolic Mode List [Toc] [Back]
A symbolic_mode_list is a comma-separated list of operations in the
following form. Whitespace is not permitted.
[who]op[permission][,...]
The variable fields can have the following values:
who One or more of the following letters:
u Modify permissions for user (owner).
g Modify permissions for group.
o Modify permissions for others.
a Modify permissions for all users (a is
equivalent to ugo).
op Required; one of the following symbols:
+ Add permission to the existing file mode
bits of who.
- Delete permission from the existing file
mode bits of who.
= Replace the existing mode bits of who with
permission.
permission One or more of the following letters:
r Add or delete the read permission for who.
w Add or delete the write permission for who.
x Add or delete the execute file (search
directory) permission for who.
s Add or delete the set-owner-ID-on-fileexecution
or set-group-ID-on-file-execution
permission for who. Useful only if u or g
is expressed or implied in who.
Hewlett-Packard Company - 1 - HP-UX 11i Version 2: August 2003
chmod(1) chmod(1)
t Add or delete the save-text-image-on-fileexecution
(sticky bit) permission. Useful
only if u is expressed or implied in who.
See chmod(2).
X Conditionally add or delete the
execute/search permission as follows:
+ If file is a directory, add or delete
the search permission to the existing
file mode for who. (Same as x.)
+ If file is not a directory, and the
current file permissions include the
execute permission (ls -l displays an x
or an s) for at least one of user,
group, or other, then add or delete the
execute file permission for who.
+ If file is not a directory, and no
execute permissions are set in the
current file mode, then do not change
any execute permission.
Or one only of the following letters:
u Copy the current user permissions to who.
g Copy the current group permissions to who.
o Copy the current other permissions to who.
The operations are performed in the order specified, and can override
preceding operations specified in the same command line.
If who is omitted, the r, w, x, and X permissions are changed for all
users if the changes are permitted by the current file mode creation
mask (see umask(1)). The s and t permissions are changed as if a was
specified in who.
Omitting permission is useful only when used with = to delete all
permissions.
Numeric Mode (Obsolescent) [Toc] [Back]
Absolute permissions can be set by specifying a numeric_mode, an octal
number constructed from the logical OR (sum) of the following mode
bits:
Miscellaneous mode bits:
4000 (= u=s) Set user ID on file execution (file only)
2000 (= g=s) Set group ID on file execution (file only)
1000 (= u=t) Set sticky bit; see below and chmod(2)
Permission mode bits:
Hewlett-Packard Company - 2 - HP-UX 11i Version 2: August 2003
chmod(1) chmod(1)
0400 (= u=r) Read by owner
0200 (= u=w) Write by owner
0100 (= u=x) Execute (search in directory) by owner
0040 (= g=r) Read by group
0020 (= g=w) Write by group
0010 (= g=x) Execute/search by group
0004 (= o=r) Read by others
0002 (= o=w) Write by others
0001 (= o=x) Execute/search by others
Options [Toc] [Back]
-A Preserve any optional access control list (ACL) entries
associated with the file (HFS file systems only). By
default, in conformance with the IEEE Standard POSIX
1003.1-1988, optional HFS ACL entries are deleted. For JFS
ACLs, this option has no effect, because optional JFS ACL
entries are always preserved. For information about access
control lists, see acl(5) and aclv(5).
-R Recursively change the file mode bits. For each file
operand that names a directory, chmod alters the file mode
bits of the named directory and all files and subdirectories
in the file hierarchy below it.
Only the owner of a file, or a user with appropriate privileges, can
change its mode.
Only a user having appropriate privileges can set (or retain, if
previously set) the sticky bit of a regular file.
If the sticky bit is set on a directory, files inside the directory
may be renamed or removed only by the owner of the file, the owner of
the directory, or the superuser (even if the modes of the directory
would otherwise allow such an operation).
In order to set the set-group-ID bit, the group of the file must
correspond to your current group ID.
If chmod is used on a symbolic link, the mode of the file referred to
by the link is changed.
EXTERNAL INFLUENCES [Toc] [Back]
Environment Variables
LC_MESSAGES determines the language in which messages are displayed.
If LC_MESSAGES is not specified or is null, it defaults to the value
of LANG. If LANG is not specified or is null, it defaults to C (see
lang(5)).
If any internationalization variable contains an invalid setting, all
internationalization variables default to C. See environ(5).
Hewlett-Packard Company - 3 - HP-UX 11i Version 2: August 2003
chmod(1) chmod(1)
International Code Set Support [Toc] [Back]
Single- and multibyte character code sets are supported.
RETURN VALUE [Toc] [Back]
Upon completion, chmod returns one of the following values:
0 Successful completion.
>0 An error condition occurred.
EXAMPLES [Toc] [Back]
Deny write permission to others:
chmod o-w file
Make a file executable by everybody:
chmod a+x file
Assign read and execute permission to everybody, and set the setuser-ID
bit:
chmod a=rx,u+s file
Assign read and write permission to the file owner, and read
permission to everybody else:
chmod u=rw,go=r file
or the obsolescent form:
chmod 644 file
Traverse a directory subtree making all regular files readable by user
and group only, and all executables and directories executable
(searchable) by everyone:
chmod -R ug+r,o-r,a+X pathname
If the current value of umask is 020 (umask -S displays
u=rwx,g=rx,o=rwx; do not change write permission for group) and the
current permissions for file mytest are 444 (a=r), displayed by ls -l
as -r--r--r--, then the command
chmod +w mytest
sets the permissions to 646 (uo=rw,g=r), displayed by ls -l as
-rw-r--rw-.
If the current value of umask is 020 (umask -S displays
u=rwx,g=rx,o=rwx; do not change write permission for group) and the
current permissions for file mytest are 666 (a=rw), displayed by ls -l
Hewlett-Packard Company - 4 - HP-UX 11i Version 2: August 2003
chmod(1) chmod(1)
as -rw-rw-rw-, then the command
chmod -w mytest
sets the permissions to 464 (uo=r,g=rw), displayed by ls -l as
-r--rw-r--.
DEPENDENCIES [Toc] [Back]
The -A option causes chmod to fail on file systems that do not support
ACLs.
AUTHOR [Toc] [Back]
chmod was developed by AT&T and HP.
SEE ALSO [Toc] [Back]
chacl(1), ls(1), umask(1), chmod(2), acl(5), aclv(5).
STANDARDS CONFORMANCE [Toc] [Back]
chmod: SVID2, SVID3, XPG2, XPG3, XPG4, POSIX.2
Hewlett-Packard Company - 5 - HP-UX 11i Version 2: August 2003 [ Back ] |
