Umask

What is a umask?

umask(1)                  User Commands                  umask(1)

NAME
     umask - get or set the file mode creation mask

SYNOPSIS
     /usr/bin/umask [ mask ]

[...]

It's important to remember this is a MASK, not a bit setting like chmod.

Easiest to show with an example:


umask 077 (or 77)
			rwxrwxrwx
mask			---rwxrwx
what comes through	rwx------	(directories)
			rw-------	(files)
	
umask 022 (or 22)
			rwxrwxrwx
mask			----w--w-
what comes through	rwxr-xr-x	(directories)
			rw-r--r--	(files)

What not to do:

umask 000 (or 0)

			rwxrwxrwx
mask			---------
what comes through	rwxrwxrwx	(directories)
			rw-rw-rw-	(files)

jgross@uiuc.edu