Automatic login

Hi, Boss
I have a question....

BackGround: i have a shell name xxxLineInput.x
the useage is: xxxLineInput.x -Txxx -Uxxx -Pxxx
when i use the command line..can run normal.
Target: i want to set automatic login, the mean is when i login the as the specifical username the shell can run automatic...

       for example: \# su test
                     then automatic login as test and run xxxLineInput.x -T.......

so i modify the /etc/passwd as below:
test:x:101:100:NMC:/XXX/xxxxxx:/XXX/xxx/xxxLineInput.x -Txxx -Uxxx -Pxxx
can not access success.

can anybody help me re-modify the /etc/passwd or give another solution for make this success.?

when i use the #su test
su: no shell

thanksverymcuh