This subchapter looks at the command separator in UNIX or Linux.
The semicolon ( ; ) is used as a command separator.
Teach Yourself UNIX/Linux System Administration and Shell Programming
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This subchapter looks at the command separator in UNIX or Linux.
The semicolon ( ; ) is used as a command separator.
You can run more than one command on a single line by using the command separator, placing the semicolon between each command.
$ date; who am i
Mon Aug 27 19:15:41 PDT 2012
admin ttys000 Aug 27 17:50
$
It does not matter if you have a space before the semicolon or not. Use whichever method is more readable and natural for you.
$ date ; who am i
Mon Aug 27 19:15:41 PDT 2012
admin ttys000 Aug 27 17:50
$
Each command is processed in order, as if you had typed each individually, with the exception that the line with the prompt is only displayed once, at the end of the series of commands.
If you forget the semicolon, you will get an error message. The following two examples are from different systems.
$ date who am i
date: illegal time format
$
$ date who am i
date: bad conversion
$
The semicolon is a common terminator or separator in many common programming languages, including Ada, C, Java, Pascal, Perl, PHP, and PL/I.
Many programmers automatically place the semicolon at the end of any shell command. The shell is fine with this.
$ date;
Mon Aug 27 19:15:41 PDT 2012
$
Coding example: I am making heavily documented and explained open source code for a method to play music for free — almost any song, no subscription fees, no download costs, no advertisements, all completely legal. This is done by building a front-end to YouTube (which checks the copyright permissions for you).
View music player in action: www.musicinpublic.com/.
Create your own copy from the original source code/ (presented for learning programming).
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Teach Yourself UNIX/Linux System Administration and Shell Programming
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†UNIX used as a generic term unless specifically used as a trademark (such as in the phrase “UNIX certified”). UNIX is a registered trademark in the United States and other countries, licensed exclusively through X/Open Company Ltd.
Names and logos of various OSs are trademarks of their respective owners.
Copyright © 2012, 2013 Milo
Created: August 27, 2012
Last Updated: December 26, 2013
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