top
From Leechfinger
All cpu
Press 1.
Full process string
Press c.
Show swap
Press f, use arrow keys to move to SWAP, press space bar to select, press esc. Swap will show on the right hand side.
Sort by something
Press f, move to the field you want to sort by, press s to sort then esc.
View number of threads and sort by it
Press f, move to nTH, press speacebar to choose, press s to sort, press esc.
Sort by memory
Press M.
Sort by CPU
Press P.
Sort by Pid
Press N.
Time running
Press T for highest time. Press M for highest mem used and time.
Display only for one user
$ top -u <user>
All idle processes
Press i.
Change priority of a process (renice)
Press r <pid>, type range -20 to 19, where -20 is the highest priority.