Run a command in a shell and keep running the command when you close the session

screen! It's the best thing since sliced bread. (Yeah, I know others have already suggested it, but it's so good the whole world should join in and suggest it too.)

screen is like, like, ummmm ... like using VNC or the like to connect to a GUI destop, but for command shell windows. You can have several shell "windows" open at once in the same screen session. You can do stuff like:

1. Start a screens session using "screen -dR" (get used to using -dR)
   • run some commands in one window
   • press CTRL-A,C to create a new window open a file there in vim
   • press CTRL-A,0 to go back to the first window and issue some command on the file you just edited
   • CTRL-A, 1 to go back to your vim session
   • CTRL-A, C for yet another window and maybe do "sudo - su" (because you just happen to need a full root shell)
   • CTRL-A, 0 and start a background process
   • CTRL-A, C to create yet a new window, "tail -f" the log for that background process
   • CTRL-A, d to disconnect your screen then CTRL-D to disconnect from the server
   • Go on vacation for three weeks
   • Log on to the server again and issue "screen -dR" to connect to your existing screen session
   • check the log in the the fourth window with CTRL-A, 3 (it's like you've been there watching it all the time)
   • CTRL-A, 1 to pick up that vim session again
   • I guess you're starting to get the picture now? =)

It's like magic. I've been using screen for longer than I can remember and I'm still totally amazed with how bloody great it is.

EDIT: Just want to mention there's now also tmux. Very much like screen, but has some unique features, splitting the windows being the most prominent one.

nohup, disown, and screen are all good but screen is the best because unlike the other two, screen allows you to disconnect from the remote server, keep everything running, and then reconnect later to see what is happening. With nohup and disown you can't resume interacting.

Try using GNU Screen. It allows you to have several shells open at once. And you can disconnect from those running shells (i.e. close session with Putty) and they will keep doing their thing.