Find and Replace Text

It works like the find and replace box of a word processor, without opening a document. There is no Replace button: the result refreshes whenever you change any box.

1. Paste your text into the Input box. It can be a sentence, a list, a data export or a block of code.
2. Type what you are looking for in the Find field.
3. Type the new text in Replace with. Leave it empty to delete every match.
4. Tick Case sensitive, Whole words only or Regular expression if you need them.
5. Read the result in the Modified text box. A note under it says how many replacements were made. Press Copy or Download .txt, or press Use as input to chain another replacement.

Your original stays in the Input box, so nothing is overwritten. With the text cat and cat, finding cat and replacing it with dog gives dog and dog and reports 2 replacements.

The match is global, so every occurrence changes, not just the first.

• Case sensitive is off by default, so Cat, cat and CAT all match. The replacement is inserted exactly as typed, so Cat becomes dog, not Dog.
• Whole words only adds word boundaries around the search. With cat replaced by dog, the text Cat category concatenate bobcat cat. becomes dog category concatenate bobcat dog. The boundary recognises only plain letters, digits and the underscore, so accented letters count as breaks and caf still matches inside café. A term that starts or ends with a symbol, such as C++, never matches as a whole word.
• Regular expression treats Find as a JavaScript pattern. Brackets, dots and dollar signs are literal when this box is off, so finding $5 and replacing it with $10 works as typed.

In regular expression mode, only the global and case-insensitive flags are used. That has three consequences: ^ and $ match the start and end of the whole text and not of each line, a dot does not match a line break, and you write \n for a line break. An invalid pattern shows Invalid regular expression and leaves the text unchanged. To build and test a pattern first, use the regex tester.

In regular expression mode the replacement can refer to what was matched: $& is the whole match, and $1, $2 are the bracketed groups.

With Whole words only on, wrap alternatives in brackets as in the last row. Without them the boundaries attach only to the first and last alternative.

• Data clean-up. Swap a delimiter, change a placeholder date or rename a product code across many rows.
• Drafts. Correct a misspelled name everywhere, or switch between spelling conventions.
• Templates. Fill in placeholders such as [DATE] one pair at a time.

If the note says 0 replacements, the pattern found nothing. Check the spelling, the case setting and whether Whole words only is blocking a match, and in regular expression mode check for special characters such as a bracket or a plus sign that need a backslash to be literal. You can always undo a change by clearing the Find field, which shows your text untouched, because the output is a separate copy and the Input box is never altered. Everything runs in your browser, so even long texts of thousands of lines are replaced without being uploaded.

The tool handles one find and replace pair per pass. For tidying whitespace, the whitespace remover and the line break remover are quicker, and the diff checker shows exactly what changed.