Huge. I was amazed at the different commands for system administration. Commands to look at different aspects of the system used in Solaris just aren't there - the commands, not the ability to view the same type of info. Just different way of doing it. Stuff like prtdiag, prtvtoc, psrinfo, ... is just not there. This page may be helpful -
unixguide.net
AIX has an unbelievable amount of lsxxx commands. I only worked with it for a short time so didn't gather a great deal of experience with it, but there is a great GUI interface for administration. Very different way of doing administration - smit was one of the tools - I'm not sure if that was the 'running man' one or not. (You click your options, hit run, and this 'running man' would run while waiting for the command to finish...very irratating. One good thing about it, it would show you the command line (if you so desire) of what you just ran.
HP-UX - use SAM for adding users, printers and such. Better than admintool (don't remember if it's a true GUI interface ).
You can probably search through this site for HP-UX for other commands (a good monitor tool is glance). HP-UX is different but not as much of a shock as AIX was.
The link I put in will show you how different each one is just for those commands/styles of doing things. Get a book on each or start looking at the different links to get more of an education. You'll be sweating it out the first few months, but you'll be better off in the long run. You never know when someone will need a person with all three and you'll be one up on the competition.
