CalcWhenRemove Duplicate Lines
The list apple, banana, apple, cherry, banana (one per line) cleans down to 3 unique lines — apple, banana, cherry — with 2 duplicates removed.
How it works
Email lists merged from three spreadsheets, inventory pasted twice, keywords collected from five tools — duplicates creep into every list. Paste the list, and the cleaned version appears in the panel in the original order, first occurrences kept, with the duplicate count printed so you know what was removed.
The case option matters more than it looks: “Apple” and “apple” are different lines to a computer and the same line to a person. Tick the box for the human rule.
The method
Lines are split on line breaks and compared exactly (or lowercased, when the case-insensitive box is ticked). The first occurrence of each line is kept, later repeats dropped; the cleaned list preserves the original order.
Frequently asked questions
Does it sort the list?
No — order is preserved exactly. Deduping and sorting are different jobs; this one keeps your order so position-based lists stay meaningful.
What about lines that differ only by spaces?
Lines are compared as typed (apart from the case option), so a trailing space makes a line technically different. That strictness is deliberate — silently trimming could merge genuinely different entries.
How many duplicates were removed?
The panel reports lines in, lines out and duplicates removed, so the cleaning is auditable before you copy the result.