sed (Stream Editor)

Advanced~30 min read

The stream editor sed excels at quick, scriptable edits across streams and files.

Core Edits

Output

Click Run to execute your code

Note: Use single quotes around sed scripts to avoid shell interpolation.

Pro Tip: Combine multiple commands with -e or use a script file for complex edits.

Caution: On macOS, sed -i requires a backup suffix: -i ''.

# Wrong
sed '2,4p' file
# Correct (suppress default print)
sed -n '2,4p' file

# Over-matching
sed -E 's/<.*>/X/'
# Safer
sed -E 's/<[^>]*>/X/g'

Task: From stdin, remove lines that are blank or start with #.

Output

Click Run to execute your code

Show Solution

sed -E '/^\s*($|#)/d'

Process structured text with awk.