Filter Lines
Drop every line that contains a pattern — or keep only the lines that do. Plain substring matching or full regex.
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How to use Filter Lines by Substring
- Paste the lines you want to filter.
- Type the substring or regex pattern.
- Pick 'Remove lines containing' or 'Keep lines containing'.
- Turn on regex or case-insensitive matching if needed.
- Copy or save the filtered result.
What is Filter Lines by Substring?
This is a browser-side mini grep: type a substring or a regular expression and either remove every matching line or keep only the matching lines. It is helpful for trimming logs, scrubbing email lists, or pulling specific entries out of a long file. The case-insensitive toggle changes both substring and regex matching.
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FAQ
- What regex flavour is supported?
- Standard JavaScript regular expressions. The case-insensitive checkbox adds the i flag for you.
- Are blank lines kept?
- Blank lines are kept unless they happen to match your pattern.