id - print real and effective user and group IDs
#id --help
Usage: id [OPTION]... [USER]
Print user and group information for the specified USER,
or (when USER omitted) for the current user.
-a ignore, for compatibility with other versions
-Z, --context print only the security context of the current user
-g, --group print only the effective group ID
-G, --groups print all group IDs
-n, --name print a name instead of a number, for -ugG
-r, --real print the real ID instead of the effective ID, with -ugG
-u, --user print only the effective user ID
-z, --zero delimit entries with NUL characters, not whitespace;
not permitted in default format
--help display this help and exit
--version output version information and exit
Without any OPTION, print some useful set of identified information.
GNU coreutils online help: <http://www.gnu.org/software/coreutils/>
For complete documentation, run: info coreutils 'id invocation'
id
Display current user and group identity.
- Display current user's id (UID), group id (GID) and groups to which they belong:
id
- Display the current user identity as a number:
id -u
- Display the current group identity as a number:
id -g
- Display an arbitrary user's id (UID), group id (GID) and groups to which they belong:
id username