PatternRegex
Find doubled words
The proofreading classic: a backreference that catches accidentally doubled words like "the the" — even across a line break.
Last updated
Matches
- It was was a mistake
- The the report
Doesn’t match
- the theory
- over and over
Why it’s written this way
The parentheses capture a word; \1 demands the exact same text again after whitespace. That is the whole trick — a backreference matches what the group MATCHED, not what it could match.
The i flag makes the backreference case-insensitive too, so sentence-start doubles like "The the" are caught. \s+ spans newlines, which is exactly where doubled words hide after editing.
Edge cases to know
- →The trailing \b is load-bearing: without it, "the theory" would count as a double.
- →Legitimate doubles exist — "had had", "that that" — so this is a reviewing aid, not a safe auto-replace.
- →Words split by punctuation ("the, the") don't match; \s+ only crosses whitespace.