id flags & options

Basic usage

Show UID, GID, and group memberships for the current user.

id

Specific user

Show info for a different user.

id www-data

-u, --user

Print only the effective user ID.

id -u

-g, --group

Print only the effective group ID.

id -g

-G, --groups

Print all group IDs the user belongs to.

id -G

-n, --name

Print names instead of numeric IDs. Use with -u, -g, or -G.

id -un

id -Gn

-r, --real

Print the real ID instead of the effective ID.

id -ru

Check if running as root

[ "$(id -u)" -eq 0 ] && echo "Running as root"