sed

Ref

CLI Option

sed [<option>] '<script>' <input file> <input file> ...

Option	Description
-i[<suffix>]	Edit files in place (makes backup if <suffix> supplied)
-r	Extended regular expressions

<script>

[<address>]<command> [; [<address>]<command> ...]

hold space ≈ clipboard

pattern space ≈ current record

Address

Address	Description
<number>	Line number
$	Last line
<first>,<last>	Line number range
<first>~<step>	Line number step
/<RegExp>/ \<character><RegExp><character>	RegExp
<address>!	Not matching <address>

Command

Command	Description
d	Delete and go to next cycle
s/<RegExp>/<replacement>/[<flags]>	Substitute RegExp
=	Print line number
h	Replace hold space with pattern space
H	Append hold space to pattern space
g	Replace pattern space with hold space
G	Append pattern space to hold space
q[<exit code>]	Quit with exit code
{ <command>; <command>; ... }	Group command

RegExp flags

Flag	Description
g	Global, replace all matches
<number>	Replace the number th match
p	Print if match
i	Case insensitive
m	Multi-line mode

RegExp capture group

Expression	Description
&	Whole matched string
\1 \2 ...	Capture group