You need to use the stat command to view or get octal file permissions for given filename. By default the ls command will not display the permissions on a file in octal form, which is useful for many commands such as chmod command and other sysadmin tasks.
This quick tutorial shows how to use the stat command to view octal file permissions.
How to get octal file permissions from Linux command line
The syntax is:
stat fileName
stat -c 'Format' file
The default output is as follows on a GNU/Linux:
$ stat /etc/passwd
Sample outputs:
File: /etc/passwd Size: 2605 Blocks: 8 IO Block: 4096 regular file Device: fd01h/64769d Inode: 15469225 Links: 1 Access: (0644/-rw-r--r--) Uid: ( 0/ root) Gid: ( 0/ root) Access: 2017-11-05 19:06:44.879876898 +0530 Modify: 2017-10-16 00:15:53.236876717 +0530 Change: 2017-10-16 00:15:53.236876717 +0530 Birth: - |
To just see octal file permissions on a GNU/Linux:
$ stat -c '%a' /etc/passwd
Sample outputs:
644
Another useful command that displays file permissions in both format:
$ stat -c '%A %a %n' /etc/passwd
Sample outputs:
-rw-r--r-- 644 /etc/passwd
Where format is as follows:
| Format | Description |
|---|---|
| %a | access rights in octal (note ‘#’ and ‘0’ printf flags) |
| %A | access rights in human readable form |
| %b | number of blocks allocated (see %B) |
| %B | the size in bytes of each block reported by %b |
| %C | SELinux security context string |
| %d | device number in decimal |
| %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 |
| %m | mount point |
| %n | file name |
| %N | quoted file name with dereference if symbolic link |
| %o | optimal I/O transfer size hint |
| %s | total size, in bytes |
| %t | major device type in hex, for character/block device special files |
| %T | minor device type in hex, for character/block device special files |
| %u | user ID of owner |
| %U | user name of owner |
| %w | time of file birth, human-readable; – if unknown |
| %W | time of file birth, seconds since Epoch; 0 if unknown |
| %x | time of last access, human-readable |
| %X | time of last access, seconds since Epoch |
| %y | time of last data modification, human-readable |
| %Y | time of last data modification, seconds since Epoch |
| %z | time of last status change, human-readable |
| %Z | time of last status change, seconds since Epoch |
A note about macOS/BSD stat command
The syntax is as follows for BSD stat command to see octal file permissions
stat fileName
stat -f "Format" fileName
The default output is as follows:
$ stat /etc/passwd
Sample outputs:
1518287693 66065 -rw-r--r-- 1 root wheel 4294967295 1724 "Oct 28 13:50:15 2017" "Oct 28 13:50:15 2017" "Oct 28 13:50:15 2017" "Oct 28 13:50:15 2017" 4096 9 0x800 /etc/passwd
To just see octal file permissions
$ stat -f "%OLp" /etc/passwd
Sample outputs:
644
To displays file permissions in both format:
$ stat -f "%Sp %OLp %N" /etc/passwd
Sample outputs:
-rw-r--r-- 644 /etc/passwd
See stat command man page for more info:
$ man stat