id

id is a command that prints out the effective and real user and group ids.

The syntax for the command is:

id [option(s)]

Useful Options / Examples

id

id [option(s)]
id [option(s)] [USERNAME]

• The id command prints out information for the current user. However, it is possible to specify a different user by appending their name to the end of the command.

Simply entering id prints out all the information about the current user.

$ id
uid=1000(biswash) gid=1000(biswash) groups=1000(biswash),4(adm),24(cdrom),27(sudo),30(dip),46(plugdev),113(lpadmin),128(sambashare),999(vboxsf)

id -u

The -u flag prints out the current user ID

$ id -u
1000

id -g && id -G

The -g flag prints out the current group id, whereas the -G flag prints out the id of all groups.

$ id -g
1000
$ id -G
1000 4 24 27 30 46 113 128 999

id -n

The -n flag is used in conjuction with the -u and the -g flags to find the name of the user or group rather than their id.

$ id -un
biswash
$ id -gn
biswash
$ id -Gn
biswash adm cdrom sudo dip plugdev lpadmin sambashare vboxsf

• The main reason to use the id command is to find to which group an user belongs to. This is helpful when switching between users with different permissions and settings.