Sed Cheatsheet

sed-cheatsheet.md

Sed Cheat Sheet

Sed command line options

sed [options] sed-command [input-file]

Option	Description	Example
-n	Suppress default pattern space printing	sed -n '3 p' config.conf
-i	Backup and modify input file directly	sed -ibak 's/On/Off/' php.ini
-f	Execute sed script file	sed -f script.sed config.conf
-e	Execute multiple sed commands	sed -e 'command1' -e 'command2' input-file

Sed commands

Command	Description	Example
p	Print pattern space	sed -n '1,4 p' input.txt
d	Delete lines	sed -n '1,4 d' input.txt
w	Write pattern space to file	sed -n '1,4 w output.txt' input.txt
a	Append line after	sed '2 a new-line' input.txt
a	Insert line before	sed '2 i new-line' input.txt

Sed substitute command and flags

 sed 's/original-string/replacement-string/[flags]' [input-file]

Flag	Description	Example
g	Global substitution	sed 's/development/production/g' .env
1,2...	Substitute the nth occurrence	sed 's/latin1/utf8/2' locale.sql
p	Print only the substituted line	sed -n 's/error_log = 0/error_log = 1/p' php.ini
w	Write only the substituted line to a file	sed -n 's/One/Two/w output.txt' words.txt
i	Ignore case while searching	sed 's/true/FALSE/i' config.php
e	Substitute and execute in the command line	sed 's/^/ls -l /' files.list
`/	^ @ !`	Substitution delimiter can be any character
&	Gets the matched pattern	sed 's/^.*/<&>/' index.xml
( ) \1 \2 \3	Group using ( and ). Use \1, \2 in replacement to refer the group	sed 's/([^,]*),([^,]*),([^,]*).*/\1,\3/g' words.txt

Read more about escaping:

• http://unix.stackexchange.com/questions/32907/what-characters-do-i-need-to-escape-when-using-sed-in-a-sh-script

Loops and multi-line sed commands

Command	Description	Example
b lablel	Branch to a label (for looping)
t lablel	Branch to a label only on successful substitution (for looping)
:lablel	Label for the b and t commands (for looping)
N	Append next line to pattern space	`sed = file.txt
P	Print 1st line in multi-line
D	Delete 1st line in multi-line

Sed hold and pattern space commands

Command	Description
n	Print pattern space, empty pattern space, and read next line
x	Swap pattern space with hold space
h	Copy pattern space to hold space
H	Append pattern space to hold space
g	Copy hold space to pattern space
G	Append hold space to pattern space