Ok I am super new to Kix and trying my best to understand everything so please bear with me on this. We had a guy that left our company that used kix for our logon script. I am getting ready to rewrite it and add some new functions.
I have searched around and cannot get a clear answer as to what these commands do:

SUBSTR(@WKSTA,1,4)

SUBSTR(@userid,1,9)

I think SUBSTR(@WKSTA,1,4) is looking for a specific workstation name but what is the ,1,4 for?
Same with the next one I think SUBSTR(@userid,1,9) is looking for a specific username but what is the ,1,9 for?

I know this must be super basic but it would help me understand what he has going on in his scripts.

Thank You