How to Use the sed Stream Editor

sed performs text transformations on files from the command line.

Replace Text

# Replace first occurrence per line\nsed 's/old/new/' file.txt\n\n# Replace all occurrences\nsed 's/old/new/g' file.txt\n\n# Replace in-place\nsed -i 's/old/new/g' file.txt

Delete Lines

# Delete line 5\nsed '5d' file.txt\n\n# Delete lines matching pattern\nsed '/pattern/d' file.txt\n\n# Delete blank lines\nsed '/^$/d' file.txt

Insert/Append

# Insert before line 3\nsed '3i\New line text' file.txt\n\n# Append after line 3\nsed '3a\New line text' file.txt