LINUX COMMAND ATLAS · COMMAND GUIDE

Linux sed command

Transform text streams; this example prints matching lines without editing files.

GNU sed

Syntax

Command form

sed [OPTION]... SCRIPT [FILE]...

6 options

Option	What it does
`-n, --quiet`	Suppress automatic printing; use p to print selected lines.
`-E, -r, --regexp-extended`	Use extended regular expressions.
`-e SCRIPT`	Add a script to the commands to be executed.
`-f FILE`	Read editing commands from FILE.
`-i[SUFFIX], --in-place`	Edit files in place; an optional suffix keeps a backup.
`-z, --null-data`	Separate input records with NUL characters.

3 examples

Transform text streams; this example prints matching lines without editing files.

sed -n "/WARN/p" app.log

Print lines 1 to 20 without printing other lines.

sed -n '1,20p' app.log

Replace every old occurrence on each line in the output.

sed 's/old/new/g' names.txt

Without -i, sed writes transformed text to standard output and leaves the source file unchanged. Test scripts on sample data first.