Repeat finder with first-occurrence display
The tool tallies every item's occurrence count, then outputs the first-seen instance of any item whose count is 2+. Items that appear once are excluded. The output is a deduplicated list of "things that repeat", not every copy of them - if `Alice` appears 3 times, she appears once in the output.
Case sensitive (off by default) and Trim (on by default) control the tally. Off/on collapses case and whitespace variants so they count together - `Apple` + `apple` counts as 2 occurrences of one item, and that item appears in the output. Turn either on to treat variants as distinct.
Order is the order of first appearance in the input. If `Alice` was seen first at line 1 and `Bob` first at line 2, `Alice` comes before `Bob` in the output - regardless of how many times each repeats.
How to use find duplicate items in a list
- 1Paste your list into the input panel
- 2Toggle Case sensitive and Trim to control how items are compared
- 3Output shows each duplicated value once, in order of first appearance
- 4Singletons (items appearing exactly once) are dropped
- 5For items that appear exactly once instead, use Find unique items
Keyboard shortcuts
Drive ListShift without touching the mouse.
What this tool actually does
Count, filter by count ≥ 2, display first-occurrence.
Emits each duplicate value once
If `Alice` appears 5 times, the output has `Alice` once. The tool reports *which items repeat*, not *every repetition*. For actual deduplication (keep one copy of every item), use Dedupe.
First-occurrence order
Items are emitted in the order they first appeared in the input. A value that first repeats near the end of the input shows up at the end of the output.
Case-insensitive comparison by default
With Case sensitive off, `Apple` and `apple` count together for the 2+ threshold. On, each casing is a distinct item - and has to appear 2+ times in exactly that casing to qualify as a duplicate.
Trim-aware by default
Trim on strips whitespace before tallying - `Apple` and ` Apple ` count together. Off treats them as distinct items that each need their own 2+ count to qualify.
Blank lines skipped
Empty lines are not counted and never appear in the output, regardless of how many of them there are.
Worked example
`Alice` and `Bob` each appear twice - both in output once. `Charlie` and `Dave` are singletons - dropped.
Alice Bob Alice Charlie Bob Dave
Alice Bob
Settings reference
How each option shapes the output using the sample above.
| Setting | What it does | Effect on the sample |
|---|---|---|
| Case sensitive: off (default) | `Apple` and `apple` tally together | `Alice` and `Bob` appear regardless of casing in source |
| Case sensitive: on | Each casing is distinct - must repeat in its own form | Only exact-case repeats qualify |
| Trim: on (default) | Whitespace-variant items tally together | `Alice` and ` Alice ` count as the same item |
| Trim: off | Whitespace-variant items distinct | `Alice` vs ` Alice ` need their own 2+ count to qualify |