GNU Screen

GNU Screen
GNU Screen with split-screen
Developer(s)	Amadeusz Sławiński and the GNU Project
Initial release	1987
Stable release	4.3.1 (June 28, 2015 (2015-06-28)) [±]
Preview release	None [±]
Development status	Active
Written in	C
Operating system	Unix-like
Type	Terminal multiplexer
License	GNU GPL v3
Website	www.gnu.org/s/screen/

GNU Screen is a terminal multiplexer, a software application that can be used to multiplex several virtual consoles, allowing a user to access multiple separate login sessions inside a single terminal window, or detach and reattach sessions from a terminal. It is useful for dealing with multiple programs from a command line interface, and for separating programs from the session of the Unix shell that started the program, particularly so a remote process continues running even when the user is disconnected.

Released under the terms of version 3 or later of the GNU General Public License, GNU Screen is free software.

Features

Further information: Terminal multiplexer

GNU Screen can be thought of as a text version of graphical window managers, or as a way of putting virtual terminals into any login session. It is a wrapper that allows multiple text programs to run at the same time, and provides features that allow the user to use the programs within a single interface productively. This enables the following features: persistence, multiple windows, and session sharing.

Screen is often used when a network connection to the terminal is unreliable, as a dropped network connection typically terminates all programs the user was running (child processes of the login session), due to the session ending and sending a "hangup" signal (SIGHUP) to all the child processes. Running the applications under screen means that the session does not terminate – only the now-defunct terminal gets detached – so applications don't even know the terminal has detached, and allows the user to reattach the session later and continue working from where they left off.

History

Screen was originally designed by Oliver Laumann and Carsten Bormann and published in 1987.^[1]

Design criteria included VT100 emulation (including ANSI X3.64 (ISO 6429) and ISO 2022) and reasonable performance for heavy daily use when character-based terminals were still common. Later, the at-the-time novel feature of disconnection/reattachment was added.

Around 1990, Laumann handed over maintenance of the code to Jürgen Weigert and Michael Schroeder at the University of Erlangen-Nuremberg, who later moved the project to the GNU Project and added features such as split-screen, cut-and-paste, and screen-sharing.^[2]

By 2014, development had slowed to a crawl. Wanting to change this, Amadeusz Sławiński volunteered to help. In response, Laumann granted him maintainership. Sławiński proceeded to put out the first new Screen release in half a decade. Because there were some unofficial "Screen 4.1" releases floating around the Internet, he called this new release "Screen 4.2.0".

References

Martin Streicher (10 Feb 2009) Speaking UNIX: Stayin' alive with Screen, IBM developerWorks
Philip J. Hollenback (22 Aug 2006) Using screen for remote interaction, Linux.com
Adam Lazur (January 2003) Power Sessions with Screen, Linux Journal, issue 105
William Von Hagen, Brian K. Jones, Linux server hacks, Volume 2, O'Reilly Media, 2005, ISBN 0-596-10082-5, pp. 155–157 (Hack #34)
Carl Albing, J. P. Vossen, Cameron Newham, Bash cookbook, O'Reilly Media, 2007, ISBN 0-596-52678-4, pp. 415–418
Dru Lavigne, BSD hacks, O'Reilly Media, 2004, ISBN 0-596-00679-9, pp. 44–48 (Hack #12)
Noah Gift, Jeremy Jones, Python for Unix and Linux system administration, O'Reilly Germany, 2008, ISBN 0-596-51582-0, pp. 300–301
Paul Mutton, IRC hacks, O'Reilly Media, 2004, ISBN 0-596-00687-X, pp. 345–349 (Hack #92)

Notes

↑ "BSD screen manager -- Part 1 of 2 - (nf)". Newsgroup: net.sources. 20 Mar 1987. Retrieved 11 Jun 2009.
↑ screen ftp

External links

Unix command-line interface programs and shell builtins

File system	cat chmod chown chgrp cksum cmp cp dd du df file fsck fuser ln ls mkdir mount mv pax pwd rm rmdir split tee touch type umask

Processes	at bg chroot cron fg kill killall nice pgrep pkill ps pstree time top

User environment	clear env exit finger history logname mesg passwd su sudo uptime talk tput uname w wall who whoami write

Text processing	awk banner basename comm csplit cut diff dirname ed ex fmt fold head iconv join less more nl paste printf sed sort spell strings tail tr uniq vi wc xargs yes

Shell builtins	alias cd echo test unset wait

Networking	dig host ifconfig inetd netcat netstat nslookup ping rdate rlogin route ssh traceroute

Searching	find grep locate whatis whereis

Documentation	apropos help man

Miscellaneous	bc dc cal expr lp od sleep true and false

List of Unix utilities

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