Find a user's UID or GID in Unix

To find a user's UID or GID in Unix, use the id command. To find a specific user's UID, at the Unix prompt, enter:

 id -u username

Replace username with the appropriate user's username. To find a user's GID, at the Unix prompt, enter:

 id -g username

If you wish to find out all the groups a user belongs to, instead enter:

 id -G username

If you wish to see the UID and all groups associated with a user, enter id without any options, as follows:

 id username