Introduction to Sed

Sed - An Introduction and Tutorial by Bruce Barnett

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Table of Contents

• The Awful Truth about sed
• The essential command: s for substitution
• The slash as a delimiter
• Using & as the matched string
• Using \1 to keep part of the pattern
• Sed Pattern Flags
• /g - Global replacement
• Is sed recursive?
• /1, /2, etc. Specifying which occurrence
• /p - print
• Write to a file with /w filename
• /I - Ignore Case
• Combining substitution flags
• Arguments and invocation of sed
• Multiple commands with -e command
• Filenames on the command line
• sed -n: no printing
• Using 'sed /pattern/'
• Using 'sed -n /pattern/p' to duplicate the function of grep
• sed -f scriptname
• sed in shell scripts
• Quoting multiple sed lines in the C shell
• Quoting multiple sed lines in the Bourne shell
• sed -v
• sed -h
• A sed interpreter script
• Sed Comments
• Passing arguments into a sed script
• Using sed in a shell here-is document
• Multiple commands and order of execution
• Addresses and Ranges of Text
• Restricting to a line number
• Patterns
• Ranges by line number
• Ranges by patterns
• Delete with d
• Printing with p
• Reversing the restriction with !
• Relationships between d, p, and !
• The q or quit command
• Grouping with { and }
• Operating in a pattern range except for the patterns
• Writing a file with the 'w' command
• Reading in a file with the 'r' command
• SunOS and the # Comment Command
• Adding, Changing, Inserting new lines
• Append a line with 'a'
• Insert a line with 'i'
• Change a line with 'c'
• Leading tabs and spaces in a sed script
• Adding more than one line
• Adding lines and the pattern space
• Address ranges and the above commands
• Multi-Line Patterns
• Print line number with =
• Transform with y
• Displaying control characters with a l
• Working with Multiple Lines
• Using newlines in sed scripts
• The Hold Buffer
• Exchange with x
• Example of Context Grep
• Hold with h or H
• Keeping more than one line in the hold buffer
• Get with g or G
• Flow Control
• Testing with t
• Debugging with l
• An alternate way of adding comments
• The poorly documented ;
• Passing regular expressions as arguments
• Command Summary
• In Conclusion
• More References

Copyright 1994, 1995 Bruce Barnett and General Electric Company

Copyright 2001,2005,2007,2011,2013 Bruce Barnett

All rights reserved

You are allowed to print copies of this tutorial for your personal use, and link to this page, but you are not allowed to make electronic copies, or redistribute this tutorial in any form without permission.

Original version written in 1994 and published in the Sun Observer

Introduction to Sed

How to use sed, a special editor for modifying files automatically. If you want to write a program to make changes in a file, sed is the tool to use.

There are a few programs that are the real workhorse in the UNIX toolbox. These programs are simple to use for simple applications, yet have a rich set of commands for performing complex actions. Don't let the complex potential of a program keep you from making use of the simpler aspects. I'll start with the simple concepts and introduce the advanced topics later on.
When I first wrote this, most versions of sed did not allow you to place comments inside the script. Lines starting with the '#' characters are comments. Newer versions of sed may support comments at the end of the line as well.

Date: 2016-01-14; view: 873