screen command in Linux provides the ability to launch and use multiple shell sessions from a single ssh session. When a process is started with ‘screen’, the process can be detached from session & then can reattach the session at a later time. When the session is detached, the process that was originally started from the screen is still running and managed by the screen itself. The process can then re-attach the session at a later time, and the terminals are still there, the way it was left. Syntax:
screen [-opts] [cmd [args]]
Options:
- -a: It force all capabilities into each window’s termcap.
- -A -[r|R]: It adapt all windows to the new display width & height.
- -c file: It read configuration file instead of ‘.screenrc’.
- -d (-r): It detach the elsewhere running screen (and reattach here).
- -dmS name: It start as daemon: Screen session in detached mode.
- -D (-r): It detach and logout remote (and reattach here).
- -D -RR: It do whatever is needed to get a screen session.
- -e xy: It change the command characters.
- -f: It make the flow control on, -fn = off, -fa = auto.
- -h lines: It set the size of the scrollback history buffer.
- -i: It interrupt output sooner when flow control is on.
- -l: It make the login mode on (update /var/run/utmp), -ln = off.
- -ls [match]: It display all the attached screens.
- -L: It turn on output logging.
- -m: It ignore $STY variable, do create a new screen session.
- -O: It choose optimal output rather than exact vt100 emulation.
- -p window: It preselect the named window if it exists.
- -q: It quiet startup. Exits with non-zero return code if unsuccessful.
- -Q: It commands will send the response to the stdout of the querying process.
- -r [session]: It reattach to a detached screen process.
- -R: It reattach if possible, otherwise start a new session.
- -S sockname: It name this session .sockname instead of …
- -t title: It set title. (window’s name).
- -T term: It use term as $TERM for windows, rather than “screen”.
- -U: It tell screen to use UTF-8 encoding.
- -v: It print “Screen version 4.06.02 (GNU) 23-Oct-17”.
- -x: It attach to a not detached screen. (Multi display mode).
- -X: It execute as a screen command in the specified session.
Shortcut keys Options:
- Ctrl-a + c: It create a new windows.
- Ctrl-a + w: It display the list of all the windows currently opened.
- Ctrl-a + A: It rename the current windows. The name will appear when you will list the list of windows opened with Ctrl-a + w.
- Ctrl-a + n: It go to the next windows.
- Ctrl-a + p: It go to the previous windows.
- Ctrl-a + Ctrl-a: It back to the last windows used.
- Ctrl-a + k: It close the current windows (kill).
- Ctrl-a + S: It split the current windows horizontally. To switch between the windows, do Ctrl-a + Tab.
- Ctrl-a + |: It split the current windows vertically.
- Ctrl-a + X: Close active Split window
- Ctrl-a + Q: Close all Split windows
- Ctrl-a + d: It detach a screen session without stopping it.
- Ctrl-a + r: It reattach a detached screen session.
- Ctrl-a + [: It start the copy mode.
- Ctrl-a + ]: It paste the copied text.
Examples:
- Installation of screen command: To install the screen command simply go to the terminal and type the following command:
sudo apt install screen
- screen: It will start a new window within the screen.
screen
- -S: It will start a new window within the screen and also gives a name to the window. It creates a session which is identified by that name. The name can be used to reattach screen at a later stage.
screen -S file
- -ls: It is used to display the currently opened screens including those running in the background. It will list all the attached as well as detached screen sessions.
screen -ls
- -d: It is used to detach a screen session so that it can be reattached in future. It can also be done with the help of shortcut key Ctrl-a + d
screen -d 1643
- Here 1643 is the screen id we want to detach.
- -r: It is used to reattach a screen session which was detached in past.
screen -r 1643
Note:
- To check for the manual page of screen command, use the following command:
man screen
- To check the help page of screen command, use the following command:
screen --help