Find and Replace

How to find and replace text online

Paste the text on the left, then type what to find and what to put in its place. The result appears on the right as you type, with every replacement highlighted where it landed.

Nothing changes until you copy it, so you can see the whole effect first.

Why the highlighting matters

Because a find and replace is easy to get slightly wrong, and the damage is invisible in a plain output box.

Replace "cat" with "dog" and you also change "concatenate". Replace "the" and you hit "there", "them" and "theatre". You do not notice in a wall of text, you notice three days later in the document you sent.

Marking every replacement makes the over-reach obvious immediately, which is the point of doing this in a browser rather than in the file itself.

Plain search does not treat your text as code

By default, what you type in the find box is searched for literally.

That matters more than it sounds. In most tools, and in every programming language, characters like . $ * + ? ( ) [ ] mean something special in a search. A dot matches any character, so searching for 1.5 also finds 145. A dollar sign means end of line and finds nothing at all.

Here those are escaped, so 1.5 finds 1.5. Turn Regex on when you actually want the special meanings.

When to turn on regex

When the thing you are looking for is a shape rather than a string.

\d+ for any run of digits, \bcat\b to match the word cat and not concatenate, \s+$ for trailing whitespace. Those are the three that cover most real uses.

If the pattern is invalid, the message appears under the box and your text is left alone. That is deliberate: typing [a-z on the way to [a-z]+ passes through invalid, and a tool that reacts to it by clearing your work is unusable.

The two things it will not do

It replaces every match, not the third one. If you need a single occurrence, make the search specific enough to hit only that.

And it does not expand $1 capture groups in the replacement. The replacement is inserted literally, which keeps a plain replacement predictable.

What often comes next

If you are cleaning up a list rather than prose, the line sorter and the duplicate line remover are usually the next two steps, in that order, since sorting makes the duplicates sit next to each other.

Everything runs in your browser. Nothing is uploaded, which is worth knowing given how often a find and replace happens on a contract or a client document.