🔍 Filtering

Regex Line Filter

The grep you wish your spreadsheet had: type a pattern and only the matching lines stay. Test and refine it live on your own data.

  • 100% free, no limits
  • No sign-up
  • Your data never leaves your browser
  • Results in under a second
Use the Regex Line Filter now ↓ Open it in the full Notepad

Free tool Paste your list — the Regex Line Filter does the rest

The example below is already loaded, so you can see exactly what you get. Replace it with your own list and the result updates as you type.

Got a bigger job? The full Notepad runs the same engine on lists of any size — chain this with dedupe, sort and filter, undo any step, and save the whole routine as a recipe for next time.

Example Regex Line Filter: before and after

Before
best running shoes 2023
best running shoes 2024
best hiking boots
After
best running shoes 2023
best running shoes 2024

How it works What the Regex Line Filter does

Keeps only the lines matching a regular expression pattern — the power-user version of Keep Lines Containing.

3 steps How to use the Regex Line Filter

  1. Paste your list into the box above — one item per line. Keyword exports, crawl exports and spreadsheet columns all work.
  2. Check the settings and adjust them to your job — the result updates as you type.
  3. Copy the result and paste it wherever it needs to go. Nothing is uploaded, so client and confidential data stay on your machine.

Use it to When to use the Regex Line Filter

  • Isolate every line that looks like a valid email address
  • Keep only keywords containing a year between 2020 and 2029
  • Extract lines matching a precise structural pattern for further analysis

FAQ Regex Line Filter questions

Is this tool free to use?

Yes. Keep Lines Matching Regex runs entirely in your browser below, with no sign-up, no limits, and nothing sent to a server.

What happens if my pattern is invalid?

The tool safely skips processing and returns your original list unchanged rather than erroring out.

Pairs well with More Filtering tools, all free

🔍 Remove Short Lines

One-word junk and broken fragments hide in every export. Set a minimum length and they are gone.

🔍 Remove Long Lines

Enforce a length limit in one click: every line longer than your number is removed, the rest stays untouched.

🔍 Negative Keyword Filter

Stop deleting junk keywords one filter at a time. Paste your whole negative list once and every line containi…

🔍 Keep Lines Containing Any Word

Carve a 50,000-row export into clean topics: paste the words that define the topic and keep only the lines th…

Stop fixing lists by hand

The Regex Line Filter is one of the free tools inside Seowolf’s Notepad. Paste a list once, then dedupe, filter, sort, compare and format it in seconds — every step undoable, nothing uploaded, no account.

Open the Notepad — it’s free
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