[CentOS] shell script question

hi all,

If I have a shell script on 5.1 that has 2 commands in the script...

command1
command2

and command1 runs until it is kill'ed by some other process. Sometimes 
command2 runs and sometimes it
doesnt (this is what it seems like).

How can I be ensured that command2 will always run after command1 is 
killed? The script is not killed
just command1.

Thanks,

jerry