I have a problem with su and su - command. Basically when I su <username>, my program works fine. If I use su - <username>, I can login without problem but when I run dbaccess (command to access database utility in informix), it gave the following errors:

"The type of terminal is unknown to the system"

FYI, I didn't get this error when I login using su <username> (without the -) and excute dbaccess command. I would appreciate if you can enlighten me. I just wonder where went wrong. Thank in advance.

su - also runs the .profile etc for the user you become, whereas su without - keeps the environment as it is set for he user you where...

So in this case the terminal type set in the .profile for whomever you become is wrong. Change it to the same as is set for yourself and you should be able to use the su -

Thanks. It is really helpful...