W (Unix)
The command w on many Unix-like operating systems provides a quick summary of every user logged into a computer, what each user is currently doing, and what load all the activity is imposing on the computer itself. The command is a one-command combination of several other Unix programs: who, uptime, and ps -a.Example
Sample output :
$ w
11:12am up 608 day, 19:56, 6 users, load average: 0.36, 0.36, 0.37
User tty login@ idle what
smithj pts/5 8:52am w
jonesm pts/23 20Apr06 28 -bash
harry pts/18 9:01am 9 pine
peterb pts/19 21Apr06 emacs -nw html/index.html
janetmcq pts/8 10:12am 3days -csh
singh pts/12 16Apr06 5:29 /usr/bin/perl -w perl/test/program.pl