umask — Set or return the file mode creation mask

Description

umask sets the file-creation permission-code mask of the invoking process to the given mode. You can specify the mode in any of the formats recognized by chmod; see chmod for more information.

The mode may be specified in symbolic (rwx) or octal format. The symbolic form specifies what permissions are allowed. The octal form specifies what permissions are disallowed.

The file-creation permission-code mask (often called the umask) modifies the default (initial) permissions for any file created by the process. The umask specifies the permissions which are not to be allowed.

umask a=rx

To calculate the permissions that will result from specific umask values, subtract the umask from 666 for files, and from 777 for directories For example, a umask of 022 results in permissions of 644.

In the tcsh shell, umask sets the file creation mask to value, which is given in octal. Common values for the mask are 002, giving all access to the group and read and execute access to others, and 022, giving read and execute access to the group and others. Without value, umask prints the current file creation mask. For more information, see tcsh — Invoke a C shell.

Options

–S

Displays the umask in a symbolic form:

u=perms,g=perms,o=perms

giving owner, group and other permissions. Permissions are specified as combinations of the letters r (read), w (write), and x (execute).

Localization

See Localization for more information.

Exit values

0

Successful completion

1

Failure due to an incorrect command-line argument, or incorrect mode

Portability

POSIX.2, X/Open Portability GuideUNIX systems.