‹ Home   ‹ Back

Sed Cheatsheet

Basic Syntax

sed [options] 'command' files

• -n: Dont output file contents
• -i: Actually change the file you are working on (use ""-i.bak" to create backup of original)
• -e: Specify multiple commands (-e 'command' -e 'command'... )
• -f: Specify a file with commands in it

Operators

• $: This means "to the end of the file/line"
• +n: This means "go an additional n times". Eg( 1,+4 ) is "start from line 1 and go 4 more lines"
• ~: This means match every step starting with some line. Eg( 1~2 ) is "start from line 1 and go every 2 lines" which would be 1,3,5...

Commands

Syntax	Name	Effect
[address-range]/p	print	Print [specified address range]
[address-range]/d	delete	Delete [specified address range]
s/pattern1/pattern2/	substitute	Substitute pattern2 for first instance of pattern1 in a line
[address-range]/s/pattern1/pattern2/	substitute	Substitute pattern2 for first instance of pattern1 in a line, over address-range
[address-range]/y/pattern1/pattern2/	transform	replace any character in pattern1 with the corresponding character in pattern2, over address-range (equivalent of tr)
[address] i pattern Filename	insert	Insert pattern at address indicated in file Filename. Usually used with -i in-place option.
g	global	Operate on every pattern match within each matched line of input

Examples

Notation	Effect
8d	Delete 8th line of input.
/^$/d	Delete all blank lines.
1,/^$/d	Delete from beginning of input up to, and including first blank line.
/Jones/p	Print only lines containing "Jones" (with -n option).
s/Windows/Linux/	Substitute "Linux" for first instance of "Windows" found in each input line.
s/BSOD/stability/g	Substitute "stability" for every instance of "BSOD" found in each input line.
s/ *$//	Delete all spaces at the end of every line.
s/00*/0/g	Compress all consecutive sequences of zeroes into a single zero.
echo "Working on it." | sed -e '1i How far are you along?'	Prints "How far are you along?" as first line, "Working on it" as second.
5i 'Linux is great.' file.txt	Inserts 'Linux is great.' at line 5 of the file file.txt.
/GUI/d	Delete all lines containing "GUI".
s/GUI//g	Delete all instances of "GUI", leaving the remainder of each line intact.