In Linux, top can be used to monitor CPU usage of the system. Top is similar to topas in AIX though both are not the same.

Question : How to monitor CPU usage in Linux?
Answer : ps command can be used to report a snapshot of the current processes in Linux. Use option aux and sort based on the column to get the top usage based on the parameter you need. If you need to get CPU then you will need to sort column 3.
Example :

[root@server ~]# watch -n 2 'echo `ps aux |head -1`;ps aux |sort -nrk 3| head -10'

Note : Above command will output top 10 processes with highest %CPU in an interval of 2 seconds. Press "Crtl C" to stop.


Question : How to monitor CPU usage in Linux?
Answer : Besides using method above, top command can be used to monitor %CPU in Linux.
Example :

[root@server ~]# top

Question : How to monitor CPU usage in Linux?
Answer : sar command can be used to monitor %CPU in Linux. Use sar with option "u" and specific the interval and numintervals needed.
Example :

[root@server ~]# sar -u 3 3

Note : Above command with execute sar -u in an interval of 3 seconds for 3 times.