Manual page for CHMOD(1V)
chmod - change the permissions mode of a file
SYNOPSIS
chmod
[
-fR
]
mode
filename
...
SYNOPSIS
/usr/5bin/chmod
[
-fR
]
mode
filename
...
AVAILABILITY
The System V version of this command is available with the
System V
software installation option. Refer to
[a manual with the abbreviation INSTALL]
for information on how to install optional software.
DESCRIPTION
Change the permissions (mode) of a file or files.
Only the owner of a file (or the super-user) may change its mode.
The mode of each named file is changed according to
mode,
which may be absolute or symbolic, as follows.
Absolute Modes
An absolute
mode
is an octal number constructed from the
OR
of the following modes:
- 400
-
Read by owner.
- 200
-
Write by owner.
- 100
-
Execute (search in directory) by owner.
- 040
-
Read by group.
- 020
-
Write by group.
- 010
-
Execute (search) by group.
- 004
-
Read by others.
- 002
-
Write by others.
- 001
-
Execute (search) by others.
- 4000
-
Set user
ID
on execution.
- 2000
-
Set group
ID
on execution
(this bit is ignored if the file is a directory;
it may be set or cleared only using symbolic mode).
- 1000
-
Sticky bit, (see
chmod.2v
for more information).
Symbolic Modes
A symbolic
mode
has the form:
[
who
]
op permission
[
op permission
] ...
who
is a combination of:
-
- u
-
User's permissions.
- g
-
Group permissions.
- o
-
Others.
- a
-
All, or
ugo.
If
who
is omitted, the default is
a,
but the setting of the file creation mask (see
umask
in
sh.1
or
csh.1
for more information) is taken into account. When
who
is omitted,
chmod
will not override the restrictions of your user mask.
op
is one of:
-
- +
-
To add the
permission.
- -
-
To remove the
permission.
- =
-
To assign the permission explicitly
(all other bits for that category, owner, group, or
others, will be reset).
permission
is any combination of:
-
- r
-
Read.
- w
-
Write.
- x
-
Execute.
- X
-
Give execute permission if the file is a directory
or if there is execute permission for one of the other user classes.
- s
-
Set owner or group
ID.
This is only useful with
u
or
g.
Also, the set group
ID
bit of a directory may only be
modified with
`+'
or
`-'.
- t
-
Set the sticky bit to save program text between processes.
The letters
u,
g,
or
o
indicate that
permission
is to be taken from the current mode for the user-class.
Omitting
permission
is only useful with
`=',
to take away all permissions.
Multiple symbolic modes, separated by commas, may be given.
Operations are performed in the order specified.
SYSTEM V DESCRIPTION
If
who
is omitted in a symbolic mode, it does not take the file
creation mask into account, but acts as if
who
were
a.
OPTIONS
- -f
-
Force.
chmod
will not complain if it fails to change the mode of a file.
- -R
-
Recursively descend through directory arguments,
setting the mode for each file as described above.
When symbolic links are encountered, their mode is not changed
and they are not traversed.
EXAMPLES
The first example denies write permission to others,
the second makes a file executable by all if it
is executable by anyone:
-
example% chmod o-w file
example% chmod +X file
SEE ALSO
csh.1
ls.1v
sh.1
chmod.2v
chown.8
Created by unroff & hp-tools.
© somebody (See intro for details). All Rights Reserved.
Last modified 11/5/97