command: who
usage: show who is logged on
options: who [option]... [ file | arg1 arg2 ]
examples:
1. To print all information regarding who is logged in
$ who -a
2. To print time of last system reboot
$ who -b
3. To print finish processes
$ who -d
4. To print only hostname and user associated with stdin
$ who -m
5. To print active processes spawned by init
$ who -p
6. To print all login names and number of users logged on
$ who -q
7. To print current runlevel
$ who -r
8. To print only name, line, and time
$ who -s
9. To print last system clock change
$ who -t
10. To add user's message status as +, - or ?
$ who -T
11. To list users logged in
$ who -u
12. To print help info of this command
$ who --help
regards,
dhanasekar