Remove duplicate lines

Client

Paste multi-line text and keep each logical line once—toggle trimming or case folding when comparisons should ignore spacing or capitalization. Pair with plain text diff when you still need side-by-side review after shrinking repeats.

Lines in → lines out

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The first occurrence of each logical line is kept; later repeats are dropped. Toggle trim or case-insensitive matching when whitespace or capitalization should not distinguish lines.

Mixed \r\n / \r breaks normalize to \n before splitting—pair with Line ending converter if you need to rewrite EOLs only.

Input lines
6
Unique lines
4
Duplicates removed
2

Live counts reflect current options; Dedupe lines writes the computed unique lines into the output panel.

Common use cases

  • Shrink log tails or CSV extracts where the same status line repeats many times.
  • Clean pasted config or host lists before diffing when only unique keys matter.
  • Prepare user-id or email lists where case or leading spaces should not create false uniques.

Common mistakes to avoid

  • Expecting order to match your source after “Sort output”

    Sorting reorders the unique lines alphabetically—it is not a stable “group by frequency” report.

  • Confusing trim with line-ending normalization

    This tool does not rewrite CRLF to LF on disk—it splits on normalized breaks for counting only. Use the line-ending converter when EOL style is the issue.

  • Assuming semantic duplicates merge

    Lines must match exactly per your trim/case rules—values that mean the same but spell differently stay distinct.

FAQ

Which duplicate is kept?

The first occurrence in top-to-bottom order is kept; later matching lines are removed.

Are blank lines deduped?

Yes—multiple empty lines collapse to one unless trimming changes how blanks compare.

Is text uploaded?

No. Splitting and dedupe run entirely in your browser tab.

Common search terms

Phrases people search for that match this tool. See the full long-tail keyword index.

  • remove duplicate lines online
  • dedupe lines text browser
  • unique lines from paste
  • collapse repeated lines tool

More tools

Related utilities you can open in another tab—mostly client-side.