Learn octal file permissions easily with stat
My SANS classmates were learning how to set and recognize file permissions on a Linux server and we realized it would be helpful to display the octal value of the permissions next to the normal rwx display. Fortunately, a quick search revealed that stat
could deliver this information:
# stat -c "%a %A %n" /usr/sbin/* | head
755 -rwxr-xr-x /usr/sbin/accessdb
755 -rwxr-xr-x /usr/sbin/acpid
755 -rwxr-xr-x /usr/sbin/addgnupghome
755 -rwxr-xr-x /usr/sbin/addpart
777 lrwxrwxrwx /usr/sbin/adduser
755 -rwxr-xr-x /usr/sbin/agetty
755 -rwxr-xr-x /usr/sbin/alternatives
755 -rwxr-xr-x /usr/sbin/anacron
755 -rwxr-xr-x /usr/sbin/apachectl
755 -rwxr-xr-x /usr/sbin/applygnupgdefaults
The first octal digit (for setuid, setgid, and sticky) is left off for any files without those bits set.
Other posts I've written (some of them might even be good) 😉