GNU Screen
GNU Screen or just Screen to its friends is an extremely useful tool to anyone who uses a proper operating system such as Linux or Solaris. What it allows you to do it run multiple terminal sessions within one terminal but not only that it allows you to detach and reattach to it. So for example if I was at work and a started a long compile process on a machine but it takes longer than I had hoped, it’s getting late and I want to go home, I can detach from the Screen session which keeps the process running. When I get home I can then reconnect to the session to check on its progress.