This subchapter looks at pipes.
Pipes are most commonly used as a method to chain different utilities together, with the output of one piped to the input of the next.
Teach Yourself UNIX/Linux System Administration and Shell Programming
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This subchapter looks at pipes.
Pipes are most commonly used as a method to chain different utilities together, with the output of one piped to the input of the next.
Ken Thompson invented the pipe in 1972.
The pipe is a standard mechanism for allowing the output of one program or process to be used as the input for another program or process.
Pipes allow the UNIX philosophy of having many small programs that each do one function very well and then write scripts that combine these small utility programs to accomplish bigger tasks.
To pipe the output of one UNIX command or utility to the next, simply place the | (vertical bar character) between the two processes:
$ cat file01.txt | sort | lp
The example obtains the contents of the designated file, sorts the contents, and then sends the result to the printer.
In June 2009, Ken Milberg named this command as one of the Top 50 universal UNIX commands at this web page Top 50 Universal INIX commands. Note that this web page requires agreeing to be spammed before you can read it.
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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Because I no longer have the computer and software to make PDFs, the book is available as an HTML file, which you can convert into a PDF.
Teach Yourself UNIX/Linux System Administration and Shell Programming
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Some or all of the material on this web page appears in the
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This web site handcrafted on Macintosh computers using Tom Bender’s Tex-Edit Plus and served using FreeBSD .
†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 Milo
Created: October 15, 2012
Last Updated: October 15, 2012
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