Line Filter
Keep only matching lines or remove matching lines using plain text or regular expressions.
Filter linesRegexClient-sideFree to use
Removed 0 lines
Keep or remove lines by text or regex without leaving the browser.
How to use
- Paste your lines. Logs, lists, or any multi-line text.
- Enter text or regex. Choose whether matches should be kept or removed.
- Copy the filtered output. Use the result for cleanup, review, or export.
Common use cases
- Filtering server logs down to error lines
- Removing unwanted rows from a text export
- Keeping only lines with a target keyword or pattern
Frequently asked questions
- What are the two filtering modes?
- Keep mode returns only the lines that match your pattern, discarding everything else. Remove mode does the opposite: it discards matching lines and returns all the non-matching ones. Switching between modes lets you isolate relevant lines or strip unwanted ones from the same input.
- Can I filter using a regular expression?
- Yes. Toggle the regex option and enter any standard regular expression. You can match patterns like error codes, IP address formats, timestamps, or any structure that plain text substring matching cannot capture on its own.
- Is matching case-sensitive?
- By default, yes. The pattern "ERROR" would not match a line containing "error". A case-insensitive toggle is available when you need to match regardless of capitalisation.
- Does my text get sent to a server?
- No. All filtering runs locally in your browser. Your text and patterns never leave your device.
- What happens if I enter an empty pattern?
- An empty pattern matches every line, so "remove matching" with an empty pattern would delete all lines. The tool either shows a warning or does nothing in that case to prevent accidental data loss.
- How does this compare to grep?
- Line Filter is a browser-based equivalent of running grep (keep mode) or grep -v (remove mode) on a file. If you are comfortable on the command line, grep is faster for large files. Line Filter is useful when you are already working in a browser, do not have terminal access, or want a quick visual result without writing a command.
Related tools
How to use
- Paste your lines. Logs, lists, or any multi-line text.
- Enter text or regex. Choose whether matches should be kept or removed.
- Copy the filtered output. Use the result for cleanup, review, or export.
Common use cases
- Filtering server logs down to error lines
- Removing unwanted rows from a text export
- Keeping only lines with a target keyword or pattern
Frequently asked questions
- What are the two filtering modes?
- Keep mode returns only the lines that match your pattern, discarding everything else. Remove mode does the opposite: it discards matching lines and returns all the non-matching ones. Switching between modes lets you isolate relevant lines or strip unwanted ones from the same input.
- Can I filter using a regular expression?
- Yes. Toggle the regex option and enter any standard regular expression. You can match patterns like error codes, IP address formats, timestamps, or any structure that plain text substring matching cannot capture on its own.
- Is matching case-sensitive?
- By default, yes. The pattern "ERROR" would not match a line containing "error". A case-insensitive toggle is available when you need to match regardless of capitalisation.
- Does my text get sent to a server?
- No. All filtering runs locally in your browser. Your text and patterns never leave your device.
- What happens if I enter an empty pattern?
- An empty pattern matches every line, so "remove matching" with an empty pattern would delete all lines. The tool either shows a warning or does nothing in that case to prevent accidental data loss.
- How does this compare to grep?
- Line Filter is a browser-based equivalent of running grep (keep mode) or grep -v (remove mode) on a file. If you are comfortable on the command line, grep is faster for large files. Line Filter is useful when you are already working in a browser, do not have terminal access, or want a quick visual result without writing a command.