ex (text editor)

ex
Original author(s)	Bill Joy
Initial release	March 9, 1978 (1978-03-09) (as part of 1BSD)
Written in	C
Operating system	Unix
Type	Text editor

ex, short for EXtended, is a line editor for Unix systems originally written by Bill Joy^[1] in 1976, beginning with an earlier program written by Charles Haley.^[2] Multiple implementations of the program exist; they are standardized by POSIX.^[3]

History

The original Unix editor, distributed with the Bell Labs versions of the operating system in the 1970s, was the rather user-unfriendly ed. George Coulouris of Queen Mary College, London, which had installed Unix in 1973, developed an improved version called em that could take advantage of video terminals. While visiting Berkeley, Coulouris presented his program to Bill Joy, who modified it to be less demanding on the processor; Joy's version became ex^[4] and got included in the Berkeley Software Distribution.

ex was eventually given a full-screen visual interface (adding to its command line oriented operation), thereby becoming the vi text editor. In recent times, ex is implemented as a personality of the vi program; most variants of vi still have an "ex mode", which is invoked using the command ex, or from within vi for one command by typing the : (colon) character. Although there is overlap between ex and vi functionality, some things can only be done with ex commands, so it remains useful when using vi.

Relation to vi

The core ex commands which relate to search and replace are essential to vi. For instance, the ex command :%s/XXX/YYY/g replaces every instance of XXX with YYY, and works in vi too. The % means every line in the file. The 'g' stands for global and means replace every instance on every line (if it was not specified, then only the first instance on each line would be replaced).

Switches

ex recognises the following switches:

- (obsolete) suppresses user-interactive feedback
-s (XPG4 only) suppresses user-interactive feedback
-l sets lisp editor option
-r recover specified files after a system crash
-R sets readonly
-t tag Edit the file containing the specified tag
-v invoke visual mode (vi)
-w set window size n
-x set encryption mode
-C encryption option
file specifies file to be edited

External links

ex: text editor – Commands & Utilities Reference, The Single UNIX® Specification, Issue 7 from The Open Group

Notes

↑ ex manual page
↑ William N. Joy, Ex reference manual, November, 1977
↑ ex – Commands & Utilities Reference, The Single UNIX® Specification, Issue 7 from The Open Group
↑ Salus, Peter H. (2005). The Daemon, the Gnu and the Penguin. Groklaw.

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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