Find & replace

Regex find and replace

Rewrite text with a pattern and a replacement, and check every change, highlighted, before you copy the result.

Find

Flags

Replace with

$3 group 3

Apply to

The whole text Each line separately

Line by line, ^, $ and the first-match-only rule restart on every line.

3 replacements

Input

Result

/posts/regex-tips/
/posts/naming-things/
/about.html
/posts/hello-world/
/blog/drafts/unfinished.html

How replacement works

The tool runs JavaScript’s String.prototype.replace in a worker and shows each replaced span with an ochre underline, so you can check the edits before copying. Without the g flag only the first match is replaced; with Each line separately, the first match of every line.

These tokens insert parts of the match into the replacement:

$1 … $99: the text of a numbered group ($10 falls back to $1 followed by 0 if there is no group 10).
$<name>: a named group; $&: the whole match.
$` and $': the text before and after the match; $$: a literal dollar sign.

Paste text, type it, or open or drop a text file onto the input; it is read in your browser and never uploaded. Line mode suits lists of paths, log lines and CSV rows: anchors work per line even without the m flag, and a pattern without g still edits every line once.

Questions

Why does only the first match change?

The g flag is off. Turn it on to replace every match, or choose “Each line separately” to replace the first match on every line.

How do I insert a literal dollar sign?

Write $$. A $ that is not followed by a valid token (for example $x) is kept as it is.

Is there a size limit?

No fixed limit; it runs in your browser. Very large texts are slower to highlight, and a replacement that takes more than two seconds is stopped.