How to use the sed command - Revision history

Benrwong: /* Substitution */

2018-10-19T18:05:17Z

Substitution

@@ Line 24: / Line 24: @@
 Notice that we surround with argument to sed with apostrophes, '.  This is the best practice when providing arguments to sed.
-sed will only change the first instance of a segment of text.  Notice how the following text has multiple instances of the same word but sed will only change the first instance.
+sed will only change the first instance in a line of text.  Notice how the following text has multiple instances of the same word but sed will only change the first instance.
   -sh-4.1$ echo water water everywhere nor any drop to drink | sed 's/water/lemonade/'
   lemonade water everywhere nor any drop to drink
 ===Examples===
   [root@he ~]# virsh list --all

Benrwong: /* Introduction */

2018-10-19T17:43:31Z

Introduction

← Older revision		Revision as of 17:43, 19 October 2018
Line 3:		Line 3:

	Usage:		Usage:
	sed [~~OPTION~~] [input file]		sed [OPTIONS] [input file]
			cat <textfile> \| sed [OPTIONS]

	===Substitution===		===Substitution===

Benrwong at 17:40, 19 October 2018

2018-10-19T17:40:40Z

← Older revision		Revision as of 17:40, 19 October 2018
Line 1:		Line 1:
	===Introduction===		===Introduction===
	sed (stream editor) allows you to manipulate text if files or ~~output~~ piped to it. You can use it to '''substitute''' certain characters, words, or numbers for different ones, selectively '''delete''' them, or choose to '''print''' relevant portions of a text.		sed (stream editor) allows you to manipulate text files or text inputs that are piped to it. You can use it to '''substitute''' certain characters, words, or numbers for different ones, selectively '''delete''' them, or choose to '''print''' relevant portions of a text.

	Usage:		Usage:
Line 18:		Line 18:
	-sh-4.1$ echo "I am fat but I will be skinny"		-sh-4.1$ echo "I am fat but I will be skinny"
	I am fat but I will be skinny		I am fat but I will be skinny
	# now with a sed command to reflect reality, substituting the word 'skinny' with a phrase 'even more fat'		# now with a sed command to reflect yours truly's reality, substituting the word 'skinny' with a phrase 'even more fat'
	-sh-4.1$ echo I am fat but I will be skinny \| sed 's/skinny/even more fat/'		-sh-4.1$ echo I am fat but I will be skinny \| sed 's/skinny/even more fat/'
	I am fat but I will be even more fat		I am fat but I will be even more fat

Benrwong at 20:48, 11 October 2016

2016-10-11T20:48:35Z

← Older revision		Revision as of 20:48, 11 October 2016
Line 15:		Line 15:
	[root@he ~]# echo UCSB \| sed 's/B/F/'		[root@he ~]# echo UCSB \| sed 's/B/F/'
	UCSF		UCSF
	And also use sed to replace a word a phrase		And also use sed to replace a word with a phrase
	-sh-4.1$ echo "I am fat but I will be skinny"		-sh-4.1$ echo "I am fat but I will be skinny"
	I am fat but I will be skinny		I am fat but I will be skinny

Benrwong: Created a quick page on sed usage for future reference

2016-10-11T20:48:03Z

Created a quick page on sed usage for future reference

New page

===Introduction===
sed (stream editor) allows you to manipulate text if files or output piped to it. You can use it to '''substitute''' certain characters, words, or numbers for different ones, selectively '''delete''' them, or choose to '''print''' relevant portions of a text.

Usage:
sed [OPTION] [input file]

===Substitution===
Use the command 'sed s/' to initiate a substitution command. After the initial 's/', you must provide it the word you would like to change, then delimit that selection with another slash, '/'. Afterwards, you will then provide another word or number you would like to change the previous entry, then again end your selection with a '/'.

Usage:
sed 's/[text_to_select]/[text_for_replacement]/'

You can use sed to correct small character mistakes:
# substitutes the letter 'B' for 'F'. Ensure your substitution command ends with a '/'
[root@he ~]# echo UCSB | sed 's/B/F/'
UCSF
And also use sed to replace a word a phrase
-sh-4.1$ echo "I am fat but I will be skinny"
I am fat but I will be skinny
# now with a sed command to reflect reality, substituting the word 'skinny' with a phrase 'even more fat'
-sh-4.1$ echo I am fat but I will be skinny | sed 's/skinny/even more fat/'
I am fat but I will be even more fat
Notice that we surround with argument to sed with apostrophes, '. This is the best practice when providing arguments to sed.

sed will only change the first instance of a segment of text. Notice how the following text has multiple instances of the same word but sed will only change the first instance.
-sh-4.1$ echo water water everywhere nor any drop to drink | sed 's/water/lemonade/'
lemonade water everywhere nor any drop to drink
===Examples===
[root@he ~]# virsh list --all
Id Name State
----------------------------------------------------
1 chi running
2 gamma running
3 beta running
[root@he ~]# virsh list --all | sed s/running/jogging/
1 chi jogging
2 gamma jogging
3 beta jogging

[[Category:Sysadmin]]