umask
PURPOSE
Displays and sets file-creation permission code mask.
SYNOPSIS
umask [ ooo ]
DESCRIPTION
The umask command sets your file-creation mask to nnn,
three octal digits that represent the read/write/execute
permissions for owner, group, and others, respectively.
When you create a file the system ANDs the complement of
nnn to 777 for directories and 666 for files, in effect
removing the corresponding permissions. (See "chmod" for
more information on file and directory permission codes.)
If you do not specify nnn, umask displays the current
value of your file-creation permission code mask. The
initial system mask (set in /etc/profile) is "022".
EXAMPLES
1. To display the current file creation mask:
umask
2. To prevent other people from writing to your directo-
ries or files:
umask 022
This sets the file creation mask to "022", which
takes away write permission for group members and
others. Directories are created with the permission
code "755". Files are created with "644".
3. To prevent other people from using your files:
umask 077
This sets the file creation mask to "077", which
removes read, write, and execute permission for group
members and others. Now files are created with per-
mission code "600".
RELATED INFORMATION
The following commands: "chmod," "csh," and "sh."
Note: The csh command contains a built-in subcommand
named ummask. The command and subcommand do not neces-
sarily work the same way. For information on the subcom-
mand, see the csh command.
The creat, chmod, mknod, open, and umask calls in AIX
Operating System Technical Reference.
The discussion of file permissions in Using the AIX Oper-
ating System.
The discussion of tailoring the user environment in Man-
aging the AIX Operating System.