I have to post this message here

trap command

My question
I'd like to use "trap" command on my unix machine sunOS 5.7.
But somehow when I do "which trap" command, it's no where to be found.

Any one knows how I can get it installed?

Thanks!!

You don't have to to post this message here. Doing so is against the rules which state:
(4) Do not 'bump up' questions if they are not answered promptly. No duplicate or cross-posting and do not report a post where your goal is to get an answer more quickly.

I will close this thread.