(Not exactly a programming question.)
Working in unix interactively, I remember that there was a command that allowed everything that was being written to the screen to also be saved in a file, but I can't remember the name of the command.
(I don't mean redirecting output of a single command. This was something that, once executed, all subsequent activity on the screen is recorded to a file, until some other key combination ended it.)
What's the mystery command?