How do I replace text in all files in a folder?

Use find with -exec sed -i, as in the commands above. Run it without -i on one file first.

How do I make a backup before sed -i?

Add a suffix: sed -i.bak. The original is saved with that ending.

Why does sed -i work on Linux but not on macOS?

macOS ships BSD sed, which requires an argument after -i. Use -i '' or -i .bak.

What does the g at the end mean?

It replaces every match on a line, not only the first.

sed: find and replace text in multiple files (sed -i)

Replace text in one file or many files with sed -i, make a backup first, and avoid the macOS and special-character mistakes.

sed edits text with an s command: s/old/new/ replaces the first match on each line, and s/old/new/g replaces every match. Add -i to change the file in place instead of printing the result.

Replace text in many files, step by step

Try it without -i first: sed 's/old/new/g' file.conf. It prints the result and changes nothing.
Back up with a suffix: sed -i.bak 's/old/new/g' file.conf.
For many files, list them with find and pass them to sed (below).
Check the result with grep -rn new . and compare with the .bak files.

Commands you can copy

Preview only

sed 's/old/new/g' file.conf

Edit in place with backup

sed -i.bak 's/old/new/g' file.conf

Edit in place, no backup

sed -i 's/old/new/g' file.conf

All .conf files in a folder tree

find . -type f -name '*.conf' -exec sed -i.bak 's/old/new/g' {} +

macOS (BSD sed)

sed -i '' 's/old/new/g' file.conf

Paths: use another delimiter

sed -i 's|/old/path|/new/path|g' file.conf

Extended regex

sed -E 's/(foo|bar)/baz/g' file.conf

Options and traps

-i[SUFFIX]: Edits the file in place. If you add a suffix, such as -i.bak, sed keeps a backup with that ending. There is no space between -i and the suffix.
-E: Uses extended regular expressions, so you can write (a|b) and + without backslashes. The sed manual calls -E the portable form.
-n: Suppresses automatic printing. Used with a p command to print only matching lines.
& in the replacement: In the replacement part, & stands for the text that matched. To write a literal ampersand, escape it as \&.
macOS error: invalid command code: macOS uses BSD sed, where -i needs an argument. Write -i '' for no backup, or -i .bak.
Slashes in paths: Pick another delimiter, such as s|/old/path|/new/path|g, instead of escaping every slash.
Special characters: In the pattern, characters such as . * [ ] are special. Escape a literal dot as \..
Config files: For generating a config from scratch, our config generators may be faster than editing by hand.

Questions about sed replace text in files

How do I replace text in all files in a folder?: Use find with -exec sed -i, as in the commands above. Run it without -i on one file first.
How do I make a backup before sed -i?: Add a suffix: sed -i.bak. The original is saved with that ending.
Why does sed -i work on Linux but not on macOS?: macOS ships BSD sed, which requires an argument after -i. Use -i '' or -i .bak.
What does the g at the end mean?: It replaces every match on a line, not only the first.

Updated 2026-10-27

sed: find and replace text in multiple files (sed -i)

Replace text in many files, step by step

Commands you can copy

Options and traps

Questions about sed replace text in files

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