10 commands you need.
1. cp - use it before you edit a file like /etc/system
2. tar cf - use it before you edit a file/configuration/move a server
3. ufsdump - use it before you change a filesystem/file/configuration/disk/move a server
4. pwd - use it before you do that rm -r ./*
5. uname -a - use it before you do that rm -r ./* (make sure you are on that host you "know" you are on)
6. ufsrestore - won't be any good if you can't bring those ufsdumps back
7. tar xf - won't be any good if you can't bring those tar'ed files back
8. man - you can find so many more commands that will cause you to need these others to get you out of trouble
9. vi - and more importantly, :q! to get out without saving.
10. exit, logout - keeps a server safe!