How To: Get Username from UID & Vice Versa in Linux

Question:

I have an UID, how do I get the username belongs to this UID in Linux?

How to Get UID from USERNAME in Linux

We usually know, there is a dedicated command called ‘id’ in linux given to find UID from username is called ‘id‘

You can use that to get the UID from the username in linux:

# id -u root
0

How to get Username from UID in Linux

Although, there is no built in command get fetch the username from the UID. We can use a pipe and regular expression match on getent to do that.

getent is a unix command that helps a user get entries in a number of important text files called databases. This includes the passwd and group databases which store user information – hence getent is a common way to look up user details on Unix.

You can use the following command to find username of the UID 752 for example in a system:

# getent passwd "752"|cut -d: -f1
texstard

getent can take group database too, although, we have used passwd database as that contains the UID of the respective linux user.