Remove Duplicate Lines
Keep only the first occurrence of each line, preserving original order. Browser-only.
0 duplicates removed
About Remove Duplicate Lines
Duplicate-line removal keeps the first occurrence of each line and drops any subsequent identical lines. Order is preserved — the output looks like your input with later duplicates erased. Use the case-sensitive and trim-whitespace options to control what counts as a duplicate.
When to use it
- Cleaning up a deduplicated list (emails, IDs, hostnames)
- Removing repeated entries from a log slice
- Producing a unique-rows version of a CSV (combine with line-count after)
- Tidying a hand-edited list before processing it further
How it works
Lines are split on LF/CRLF. Each line is keyed against a Set; if the key has been seen, the line is dropped. The case-sensitivity toggle controls whether the key is lowercased; the trim toggle controls whether leading/trailing whitespace is normalized before comparison.
Examples
apple banana apple cherry banana
apple banana cherry
Frequently asked questions
- Is line order preserved?
- Yes. The first occurrence of each line keeps its position; only the later duplicates are removed.
- What about case differences?
- By default, comparison is case-sensitive — 'Apple' and 'apple' are different. Toggle the option to merge them.
- Are surrounding spaces treated as significant?
- By default yes — 'foo' and ' foo' are different. Enable the trim option to ignore leading/trailing whitespace.