Of course i did but i'm still having issues, that's why i was asking for help. for example, i have these two problems:

1. I used this form below to allow user Greg to login as generic user "devuser" which it worked fine with one problem: I want it to ask for a password so user "Greg" has to enter (his own password), but the problem is it doesn't ask for a password.

Greg server_name = (devuser) PASSWD: SHELLS, $CMD

2. If i don't want Greg to use a shell when sudo, how can i do that? in other word:
now Greg sudo as follow:
# sudo -u devuser tcsh

How can he sudo if i don't want him to use any shell like tcsh?