I have RHEL 4 (Red Hat Enterprise Linux 4), installed on two machines. On one of this (machine 1), I made an installation "basic", i.e I have not used the extra CD. On the other (machine 2) I used this CD, which I found KSH, so I installed that. But surprise, I found myself with KSH on both (I want), but especially with two different versions of KSH. If I could identify version KSH, AC I would have fewer problems, but this is not the case: In the man ksh, it is clear that KSH set an environment variable, KSH_VERSION. Now on the machine 2, this variable is not present when I am in ksh. Is there a way to know what is the shell used in a given terminal? Any help on this is appreciated. Thanks in advance.