Sed Cheat Sheet

sed: stream editor " " vs ' ' 单引号不会执行parameter expansion，但双引号会 sed执行多个命令: sed -i "cmd1; cmd2; cmd3" input.txt $ 表示最后一行

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`

Command	Description	Example
`p`	Print pattern space	`sed -n '1,4 p' input.txt` # 1, 4: line number to express line 1 to 4
`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`
`i`	Insert line before	`sed '2 i new-line' input.txt`

 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 /e' 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`

in case backreference does not work, use ( and ) instead

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

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