Q. I need to find file permission and store the same to a shell variable. How do I find out the file permission without parsing ls -l output?

A. Use GNU stat command to display file or file system status. It has option to display output in specific format.

Display stat for /etc/passwd file

Type the following command:
$ stat /etc/passwd
Output:

  File: `/etc/passwd'
  Size: 1675            Blocks: 8          IO Block: 4096   regular file
Device: 802h/2050d      Inode: 7899368     Links: 1
Access: (0644/-rw-r--r--)  Uid: (    0/    root)   Gid: (    0/    root)
Access: 2007-12-05 08:20:31.000000000 +0530
Modify: 2007-12-04 23:36:50.000000000 +0530
Change: 2007-12-04 23:36:50.000000000 +0530

Print access rights in octal format:
$ stat -c %a /etc/passwd
Output:

644

Print access rights in human readable format, enter:
$ stat -c %A /etc/passwd
Output:

-rw-r--r--

Store access rights in octal format to a shell variable:
$ VAR=$(stat -c %a /etc/passwd)
$ echo $VAR

Other valid format sequences for files

• %b : Number of blocks allocated (see %B)
• %B : The size in bytes of each block reported
• %d : Device number in decimal
• %C : SELinux security context
• %D : Device number in hex
• %f : Raw mode in hex
• %F : File type
• %g : Group ID of owner
• %G : Group name of owner
• %h : Number of hard links
• %i : Inode number
• %n : File name
• %N : Quoted file name with dereference if symbolic link
• %o : I/O block size
• %s : Total size, in bytes
• %t : Major device type in hex
• %T : Minor device type in hex
• %u : User ID of owner
• %U : User name of owner
• %x : Time of last access
• %X : Time of last access as seconds since Epoch
• %y : Time of last modification
• %Y : Time of last modification as seconds since Epoch
• %z : Time of last change
• %Z : Time of last change as seconds since Epoch

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