Remove Duplicate Lines

Remove duplicate lines from a list or text block and report how many were dropped. Useful for cleaning up CSVs, log files, URL lists, keyword dumps, and any place repeats sneak in.

Keep mode:

• First occurrence — when a line appears more than once, the first copy is kept and later copies removed. This is the usual choice: it preserves the original top-to-bottom order you pasted.
• Last occurrence — the last copy is kept instead. Handy when the most recent entry is the one you trust (e.g. a log where the latest line supersedes earlier ones).

Comparison options:

• Case sensitive (default on) — treats Apple and apple as different lines. Turn it off to treat them as duplicates.
• Trim whitespace before comparing — strips leading/trailing spaces and tabs on each line before deciding if two lines are equal, so hello and hello count as the same line. (Trimming is used only for comparison; the original spacing in kept lines is preserved in the output.)
• Ignore empty lines — drops empty lines (lines with no characters or only whitespace) entirely, rather than collapsing them to one.

Good to know:

• Whole-line comparison only — this tool does not deduplicate individual words or fields within a line.
• Counts in the metadata tell you the original line count, the kept line count, and exactly how many duplicates were removed, so you can confirm the cleanup.