GNU Screen is a terminal multiplexer, a software that can be used to multiplex several virtual consoles, allowing a user to access multiple separate login session inside of a single terminal window, or detach and reattach session from a terminal.
Following contains some useful config and screenrc for GNU screen.
edit or create /etc/screenrc or ~/.screenrc and add below code. This code adds a nice status bar to the default screen.
autodetach on
startup_message off
hardstatus alwayslastline
shelltitle 'bash'
hardstatus string '%{wk}%?%-Lw%?%{=b kR}(%{W}%n*%f %t%?(%u)%?%{=b kR})%{= w}%?%+Lw%?%? %{g}]'
Execute this command
screen
This will create a screen session with name pts-0.hostname.
To detach the screen press Ctrl+a d
Most of commands follow Ctrl+a as a prefix.
Now since we are detached from screen we can list all currently running screens using screen -ls
We can name a new screen created using this command.
screen -S cowscrem
This creates a screen session with name cowscream.
To reattach to a screen we can type
screen -r <screen_pid> or screen -r <screen_name>
To send a command to screen session and execute a command
screen -X -S 12108 quit
sends kill signal to screen with pid 12108
Next Screen window : Ctrl+a n
Previous Screen window : Ctrl+a p
Kill screen window : Ctrl+a k
Create a new screen window : Ctrl+a c
Kill all windows : Ctrl+a \
List all windows : Ctrl+a ""
To rename the screen window Ctrl+a A
Vertical Split : Ctrl+a |
Horizontal Split: Ctrl+a S
Move to next pane : Ctrl+a tab
To open a window on next pane : Ctrl+a <window_no> or Ctrl+a ""
removing a pane : Ctrl+a x
screen -d -m python counter.py
Note: screen will terminate as soon as your program finishes.
additionally u can list all options
Ctrl+a ?
and you can run names of commands
Ctrl+a :screenname cowsayshello
say u wanna resize the horizontal pane to 30 chars or use percentage
Ctrl+a :resize -h 30
Ctrl+a :resize -h 30%
Cannot make directory /run/screen : Permission denied , this happens due to sudden restart or process ``/etc/rcS.d/s70screen-cleanup` is running via upstart much earlier than expected to run, and is failing to correctly clean up that directory.
It can be fixed with command
sudo /etc/init.d/screen-cleanup start