Filter Lines
Quickly filter a list of lines by a keyword or pattern. Keep lines that match, exclude lines that match, or use powerful regular expressions. Great for cleaning data, extracting relevant entries, or removing unwanted content. No signup, no uploads — everything happens right here in your browser.
Why use this Filter Lines tool?
When you have a long list and only need certain entries, manually deleting lines is tedious. This tool lets you instantly keep or remove lines based on a simple text match or a regular expression. It's perfect for log files, data dumps, and any text where you need to isolate relevant content.
- Two filter modes – keep lines containing a match, or remove them to see only non‑matching lines.
- Case sensitivity toggle – decide whether "Error" and "error" are treated as different.
- Regex support – unleash pattern matching for complex queries (e.g.,
\d{3}-\d{2}-\d{4}for SSNs). - Instant preview – results update as you type (with a short delay) or when you click Filter.
- 100% private – all processing is local; your data never leaves your device.
How to filter lines (step‑by‑step)
1. Paste your lines
Drop the text containing the lines you want to filter into the left box.
2. Set the filter
Type the keyword or pattern you're interested in. Choose whether to keep or remove matching lines.
3. Tune sensitivity
Enable case sensitivity if needed, or check "Use regex" to use a regular expression pattern.
4. Copy or download
The filtered lines appear on the right. Use the buttons to copy to clipboard or save as a .txt file.
Example: filtering error logs
| Input lines | Filter: keep lines containing "error" (case insensitive) |
|---|---|
| INFO: Server started ERROR: Connection failed DEBUG: Processing request ERROR: Timeout occurred | ERROR: Connection failed ERROR: Timeout occurred |
Common use cases
- Log analysis: Extract only warning or error lines from server logs.
- Data cleaning: Remove irrelevant entries from a CSV or data dump before import.
- Code filtering: Keep only lines containing certain function names or variables.
- Email lists: Separate addresses containing a specific domain.
Pro tips
- If you need to filter by multiple keywords at once, use a regex with alternation:
error|fail|critical. - The filter checks if the pattern appears anywhere in the line, not just at the beginning.
- Combine with our Text Sorter or Duplicate Line Remover after filtering for further cleanup.