## page was renamed from HowToUCC/Screen
Once you're connected to one of UCC's servers you'll want to start running things. Unfortunately you only have a single terminal interface which can only run a single foreground process at a time. You could open up a [[HowToUCC/SSH|SSH]] session for every program you want to run, or you could use a terminal multiplexing program like [[https://savannah.gnu.org/projects/screen|screen]] or [[https://tmux.github.io/|tmux]] . Terminal multiplexers also allow you to keep processes running even once you terminate your SSH session.

== Screen ==
Once you have connected to the server via [[HowToUCC/SSH|SSH]], run {{{screen}}}. This will launch the program and give you a terminal window that won't disappear when you disconnect from {{{ssh}}}. If you disconnect or log out, then want to reattach the the session you were previously running, log back in and type: {{{screen -dR}}}

|| '''Command''' || '''Key Combination'''<<BR>>(Case Sensitive) || '''Action''' ||
|| screen || Ctrl + a then c || Create/open a new window ||
|| kill   || Ctrl + a then k || Kill the current window (typing {{{exit}}} from the window achieves a similar result) ||
|| detach || Ctrl + a then d || Detach this session (the windows continue to run), use {{{screen -r}}} to reattach later ||
|| windowlist || Ctrl + a then " || List all windows and switch between them interactively ||
|| title  || Ctrl + a then A || Set the title for the screen window ||
|| next   || Ctrl + a then n || Go to the next screen window ||
|| prev   || Ctrl + a then p || Go to the previous screen window ||
|| help   || Ctrl + a then ? || Display the help window with the command keys (bindings) ||

A full list of command keys (bindings) can be found in the {{{man}}} page for {{{screen}}} under the section "Default Key Bindings".

If your screen stops responding, try pressing "Ctrl + a then Ctrl + q" and "Ctrl + q". You may have accidentally frozen it yourself due to [[https://unix.stackexchange.com/questions/12107/how-to-unfreeze-after-accidentally-pressing-ctrl-s-in-a-terminal|flow control commands]] .

== Tmux ==
After logging in to the server, simply run {{{tmux}}} to begin. You will be placed into a new terminal window from which you can run commands as usual. Tmux's "prefix" key is <C-b> (i.e. "Ctrl + b") so that one can run {{{screen}}} inside {{{tmux}}} or vice versa without clashing). Type that, then type a command key to perform actions such as switching windows, detaching, adding a new window, etc. Similar to {{{screen}}}, detaching {{{tmux}}} allows you to keep processes running after terminating your session. A few useful command keys include:

|| '''Command''' || '''Key Combination'''<<BR>>(Case Sensitive) || '''Action''' ||
|| new-window    || Ctrl + b then c || Create/open a new window ||
|| detach-client || Ctrl + b then d || Detach this session (the windows continue to run), use {{{tmux attach}}} to reattach later ||
|| choose-tree   || Ctrl + b then w || List all windows and switch between them interactively ||
|| kill-pane     || Ctrl + b then x || Kill the current window (typing {{{exit}}} from the window achieves a similar result) ||
|| list-keys     || Ctrl + b then ? || Display the help window with the command keys (bindings) ||

A full list of command keys (bindings) can be found in the {{{man}}} page for {{{tmux}}} under the section "Default Key Bindings".