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GNU Screen

Any system that doesn't have tmux will almost always have screen.

Table of Contents

Building from Source

Build from source to enable 256color support.

curl -O https://ftp.gnu.org/gnu/screen/screen-4.9.1.tar.gz
tar -zxvf screen-4.9.1.tar.gz

sh autogen.sh                                 &&
./configure --prefix=/usr                     \
            --enable-colors256                \
            --infodir=/usr/share/info         \
            --mandir=/usr/share/man           \
            --with-socket-dir=/run/screen     \
            --with-pty-group=5                \
            --with-sys-screenrc=/etc/screenrc &&

sed -i -e "s%/usr/local/etc/screenrc%/etc/screenrc%" {etc,doc}/* &&
make

Basics

  • screen

    • Starts a new screen session.

  • screen -ls

    • This lists all screen sessions.
    • Tmux has the same thing (as tmux ls)

  • screen -r [processid]

    • This reattaches to the given process.
    • If there's no [processid], it will reattach to the last screen session.

  • screen -S [name]

    • This starts a new screen session with the given name.

  • screen -R [name]

    • This reattaches to a running screen session with the given name.
    • If the session doesn't exist, it will be created.

  • screen -d [processid]

    • This detaches from the given process.
    • <C-a>d is the shortcut for this.

Default Keybindings:

Screen's default <leader> is <Ctrl-a> Since this can be changed, I'll use <leader> to refer to it.

  • C-a is the prefix/leader.
  • <leader> ? for a list of keybindings.
  • <leader>w (or <leader>w) will show which window is active
  • <leader>0: will take you to screen 0
  • <leader>:: will take you to screen command line
  • <leader>:help<CR>: shows help
  • <leader>c: Create a new window.
  • <leader>aa: Hop between screen windows
  • <leader>d: detaches from current window
    • screen -r to reattach
  • <leader>|: Split window vertically. (i.e., <Shift>\)
  • <leader>\: Kill all windows and terminate screen
    • Don't use this unless know you definitely want to.

Copy mode

  • <leader>[: Enter copy mode
    • Select text with <enter(or space)> motion <enter>
  • <leader>]: Paste from screen buffer

To paste into vim/nvim:

  • :set paste
  • i
  • <leader>]

Regions

Regions don't take on their own terminal instance like in tmux.
You can use them to access other windows.
i.e., You can use a region to access window 2 while working in window 1.

Working with regions (called panes in tmux):

  • C-a S Splits the screen horizontally (capital S).
  • C-a | Splits the screen vertically. (not \, that kills all the windows).
  • C-a C-i switches between regions (panes).
  • C-a C-tab also switches between regions (panes).
  • C-a Q Kills all regions except the current one.

Screen Sharing with Multiuser Sessions

To share screen session with another user:

  • <leader>:multiuser on
    • <leader> and then : to enter command mode
    • :multiuser on to enable multi-user support

Get the screen session with <leader>d (detach) and screen -ls

Then other user will connect with screen -S [session_name]

This feature of Screen has more robust multi-user support than tmux.

Useful Commands for Multiuser Sessions

  • :displays: Lists all the currently connected user front-ends (displays).
    • In this interface you can detach displays.
      • d in the :displays interface to detach that display.
      • D in the :displays interface to force detach that display.
    • <space> while in this interface to refresh the list.

The following is an example of what displays could look like:

  xterm 80x42 jnweiger@/dev/ttyp4     0(m11)   &rWx  
  facit 80x24 mlschroe@/dev/ttyhf nb 11(tcsh)   rwx  
  xterm 80x42 jnhollma@/dev/ttyp5     0(m11)   &R.x  
   (A)   (B)     (C)     (D)      (E) (F)(G)   (H)(I)
The legend is as follows:

  • (A): The terminal type known by screen for this display.
  • (B): Displays geometry as width x height.
  • (C): Username who is logged in at the display.
  • (D): Device name of the display or the attached device
  • (E): Display is in blocking or nonblocking mode. The available modes are "nb", "NB", "Z<", "Z>", and "BL".
  • (F): Number of the window
  • (G): Name/title of window
  • (H): Whether the window is shared
  • (I): Window permissions. Made up of three characters.