Intro To 'groups' Command In Linux

2023-05-25 - By Robert Elder

     I use the 'groups' command to list all of the groups that a user belongs to:

groups

robert adm dialout cdrom sudo dip plugdev lpadmin lxd sambashare

     By default, the group memberships that are shown are for the current user.  You can explicitly specify a user to see group memberships for that user as well:

groups postgres

postgres : postgres ssl-cert

     The set of groups that a user belongs to will determine if that user has the ability to access certain files or system resources.

     The permission settings related to groups can be seen using the 'ls -l' command.  Here is an example that shows the group permissons on some interesting files:

ls -l /dev/{input/event0,tty} /etc/shadow some-file.txt

     the group permissions are highlighted here:

     and the group ownerships are highlighted here.

     And that's why the 'groups' command is my favourite Linux command.