π§ Duplicate Line Remover
Remove duplicate lines, sort, and clean up text lists.
How to Use This Tool
Paste any list of items, one per line, into the input box. Configure the options to match your data, then click Remove Duplicates. The output shows only unique lines with a count of how many were removed.
Paste your list into the input box, with one item per line.
Choose options: case-insensitive matching, trimming whitespace, and whether to remove blank lines.
Select a sort order: original position, A to Z, or Z to A.
Click Remove Duplicates and copy your cleaned list from the output.
Order-Preserving vs Sorted Deduplication
The way duplicates are removed matters depending on your data. Original order mode keeps the first occurrence of each line and discards all later duplicates, which is what you want when the order carries meaning, for example a priority-ranked keyword list or a changelog where the first mention of an item is the canonical one. Sort modes alphabetize after deduplication, which is useful for creating clean reference lists, sorted domain lists, or deduplicated tag sets where order does not matter. Case-insensitive matching treats "Apple", "apple", and "APPLE" as the same line, outputting whichever form appeared first. This is usually the right setting for email address lists since mail servers typically treat addresses as case-insensitive. The Trim Whitespace option handles the common case where data came from a spreadsheet or CSV where some lines have leading or trailing spaces, causing them to appear unique when they are actually duplicates. Run this before deduplication to normalize the data first.
Common Use Cases
Frequently Asked Questions
How does duplicate line removal work?
The tool splits text into lines, builds a set of unique lines (preserving first occurrence), and outputs them in original or sorted order.
Is the comparison case-sensitive?
You can choose: case-sensitive (exact match) or case-insensitive (treats "Hello" and "hello" as duplicates). Our default is case-sensitive.
Can I remove blank lines too?
Yes, enable the "Remove empty lines" option to filter out blank and whitespace-only lines in the same pass.
What is a good use case for this tool?
Cleaning email lists, deduplicating keywords, filtering log files, processing CSV column data, and removing repeated entries from any list.
Can I sort the output?
Yes β choose alphabetical ascending, alphabetical descending, or original order.