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Regex Line Extractor

Extract matching lines using a JavaScript regex and explicit flags in a time-limited local worker.

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Regex Line Extractor input

Text

Regex pattern

JavaScript pattern source without slash delimiters.

Flags

gimsuyd

Line operations recognize CRLF, LF and CR and normalize mixed endings to the first encountered separator. A terminal newline is a terminator, not an extra record. Empty text has zero records.

Each line is tested independently with regex state reset. No flags are initially selected. Requires a disposable local worker with a 1,500 ms timeout; unsupported flags and invalid patterns fail clearly.

Matches remain in source order, including duplicates. Output is inert text, never opened or fetched. At most 10,000 matches are returned; exceeding this limit produces an error.

Limits: 1,000,000 input UTF-16 code units, 4,000,000 output code units and 100,000 lines. Oversized inputs or results fail explicitly; nothing is silently truncated. Larger work uses a local worker with a 10-second timeout.

Matching lines

Your result will appear here after you extract matching lines. Editing an input clears the previous result.

Processed locally in your browser. Inputs and results are not uploaded or saved by this page.

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What does this tool do?

Extract matching lines using a JavaScript regex and explicit flags in a time-limited local worker. Inputs: Text, Regex pattern, Flags. Outputs: Matching lines, Match count.

How to use it?

Enter text and a JavaScript pattern, then select any flags to apply to each line. Choose “Extract matching lines”, then copy individual result values if needed. Clear removes the inputs and results and restores all option defaults.