Macintosh Terminal Pocket Guide

Name

umask — stdin  stdout  - file  -- opt  --help  --version

Synopsis

umask [options] [mask]

The umask command sets or displays your default permission mode for creating files and directories: whether they are readable, writable, and/or executable by yourself, your group, and the world:

➜ umask            Display as octal number
0002
➜ umask -S         Display as characters
u=rwx,g=rwx,o=rx

Your umask specifies permissions to be removed by default from files and directories you create. With a umask value of zero, files get created with mode 666 (rw-rw-rw) and directories with mode 777 (rwxrwxrwx).^[12] Any other umask value gets subtracted from these default modes. For example, if you set your umask to 002:

➜ umask 002

your default mode for files will be 666 minus 002, or 664, which is rw-rw-r--. For directories, it will be 777 minus 002, or 775, which is rwx-r-xr-x.

Here are some common values for your umask. Use mask 0022 to give yourself full privileges, and all others read/execute privileges only:

➜ umask 0022
➜ touch newfile1 && mkdir dir1
➜ ls -ld newfile1 dir1
drwxr-xr-x    2 smith staff     4096 Nov 11 12:25 dir1
-rw-r--r--    1 smith staff        0 Nov 11 12:25 newfile1

Use mask 0002 to give yourself and your default group full privileges, and read/execute to others:

➜ umask 0002
➜ touch newfile2 && mkdir dir2
➜ ls -ld newfile2 dir2
drwxrwxr-x    2 smith staff     4096 Nov 11 12:26 dir2
-rw-rw-r--    1 smith staff        0 Nov 11 12:26 newfile2

Use mask 0077 to give yourself full privileges with nothing for anyone else:

➜ umask 0077