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How can I set up a different umask for directories then files?

I need dirs with umask 003 and files with umask 117

  • Sorry, there's just one umask. BTW, 003 for directories seems weird: why would you allow other-read, but not other-execute? That will allow listing the directory, but not accessing any of the files in it. – Barmar Jan 13 '17 at 16:39
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umask is global in bash. One thing you could do is to create a mkdir wrapper(a script, you give the name to it) that would change the mask after executing it.

#!/bin/bash
umask 0701 ; /path/to/real/mkdir $1 ; umask 0604

This was answered here:

Remember: For directories, the base permissions are (rwxrwxrwx) 0777 and for files they are 0666, meaning, you will not achieve execute permissions on file creation inside your shell even if the umask allows. This is clearly done to increase security on new files creation.

Example:

[admin@host test]$ pwd
/home/admin/test
[admin@host test]$ umask
0002
[admin@host test]$ mkdir test
[admin@host test]$ touch test_file
[admin@host test]$ ls -l
total 4
drwxrwxr-x 2 admin admin 4096 Jan 13 14:53 test
-rw-rw-r-- 1 admin admin    0 Jan 13 14:53 test_file

umask Unix Specification tells nothing about this file permission math specifics. It's up to the shell developers to decide(and OS makers).

  • 3
    umask is per process, but inherited, rather than global. In the wrapper script there is no need to reset the umask after the real mkdir has completed, it will just cange the umask for the shell running the script, which is just about to exit anyway. Removing the umask will allow the return code of the real mkdir, as an extra bonus. – icarus Jan 13 '17 at 20:03
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Please note that the standard mkdir command has an -m option to set the permission bits at creation time:

-m mode

Set the file permission bits of the final created directory to the specified mode. The mode argument can be in any of the formats specified to the chmod(1) command. If a symbolic mode is specified, the operation characters + and - are interpreted relative to an initial mode of a=rwx.

In your case you could set the umask to whatever you need for the permissions of your files, and use the -m option for the folder creation.

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