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UNIX in a Nutshell: System V Edition

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UNIX Commands
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Print the current value of the file creation mode mask, or set it to value , a three-digit octal code specifying the read-write-execute permissions to be turned off. This is the opposite of chmod . Usually used in .login or .profile . umask is available as a built-in command in the Bourne and C shells (see Sections 4 and 5).

umask Number

File Permission

Directory Permission

0 rw- rwx
1 rw- rw-
2 r-- r-x
3 r-- r--
4 -w- -wx
5 -w- -w-
6 -- -x
7 -- --


Turn off write permission for others:

umask 002	
Produces file permission 

Turn off all permissions for group and others:

umask 077	
Produces file permission 

Note that you can omit leading zeroes.

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