It happens quite often that while I'm in the Terminal I issue a command for which I don't have enough privileges.
For instance: sudo ipfw list
will list all the currently active rules for the firewall. If you happen to forget the sudo part however, all you will see is a warning: ipfw: socket: Operation not permitted
You'll have to reenter the command again with the sudo part before it.
I knew there was a special command in tcsh that would repeat the previous command however what it was eluded me. Today I got tired of that and actually did some digging and come up with the following: Survival guide to the Unix shell tcsh
It states that !!
repeats the previous command, so if you type sudo !!
after a failed attempt you will save yourself some time.
The guide contains some more useful tips but if all you pick up is this one rejoice!!