Some useful key commands are as follows:
g - generic info (default)
m - memory details
d - disk details
n - network details
s - scheduling and thread-group info
v - various info (ppid, user/group, date/time, status, exitcode)
c - full command-line per process
..to name but a few.
One feature I especially like is atop highlights in red colour the processes that may be misbehaving, such as CPU, memory or disk I/O hoggers; very helpful when a rogue program is killing your machine or sucking away power or I/O.
To install atop, simply use:
sudo apt-get install atop
Below are some screen shots:
atop highlighting CPU hogging
atop highlighting I/O hogging
So, while I may always turn to ps,top or vmstat as my first port of call when I want to check my systems activity, atop is another very useful utility in my toolkit that comes in useful in seeking and resolving misbehaving systems. Check it out and let me know what you think!