Lightning Talk - Screen (Terminal Multiplexing)

screen_notes.md

Terminal Multiplexing and YOU!

Screen gives you a terminal which can persist after your SSH connection has closed.

Reasons to use a terminal multiplexer:

• Run a lengthy program (crunching, or a Minecraft server, etc.) even after you disconnect.
• Allows you to resume working exactly where you left off, after your connection breaks or you switch computers.
• Additionally gives you a sort of "tab"-like interface for terminals.

How to use screen:

1. SSH into your server. Screen is pretty ubiquitous on server environments.
2. Type the command "screen" to begin a new screen session.
3. Profit!!

Screen basics:

• Every screen has a name. This is how you get back to it later.

Navigating Screen:

=======================================================================================
                   Outer Terminal: 
  Command                               Description     
=======================================================================================
screen                   Opens a new screen.
screen -S [name]         Creates a screen 
screen -ls               Lists all open screens and their names.
screen -r [name]         Reattaches the screen whose name begins with [name].

=======================================================================================
                   Inside A Screen: 
  Key Sequence                          Description     
=======================================================================================
Ctrl+a, d                 "Detaches" the screen and returns you to outer terminal.
Ctrl+a, c                 Creates a new "tab" in the open screen.
Ctrl+a, (p, n, or Ctrl+a) Flips through your open tabs (previous, next, or last selected)
Ctrl+a, [number]          Goes to the n-th tab that's open.
Ctrl+a, "                 "Select a 'tab'" menu.

Cons of Screen:

• Is no longer actively developed (latest version came out in 2008).
• Has little-to-no user interface.

Enter Tmux!

There are other terminal multiplexers! Check out tmux! $ sudo apt-get install tmux

Similar key bindings to screen

Except by default it uses Ctrl+b as its hotkey. You can change this by placing the following three lines in ~/.tmux.conf

set -g prefix C-a
unbind C-b
bind C-a send-prefix

Differences from screen

Then it should be similar to screen. Except for the following differences:

• Sort of "task bar" down at the bottom tells you what program is running and where you currently are.
• Tmux sessions are identified by a small number starting at 0, this number is the leftmost number in the task bar.
• To get back into session n, the command is tmux attach -t[n], but if you only have one, you can leave out the -t part.

So hopefully that gives you a bit of a primer on what your workflow could look like with a more flexible terminal provided by screen or tmux.