Duplicate Line Remover: Deduplicate Text Instantly

When working with lists, log files, or data exports, duplicates are inevitable. Our duplicate line remover identifies and removes repeated lines while preserving the original order — the first occurrence of each line is kept.

How It Works

The tool processes text line by line:

1. Each line is checked against previously seen lines
2. If a line is new, it’s kept and added to the “seen” set
3. If a line has been seen before, it’s removed
4. The result contains only unique lines in their original order

Example

Input:

apple
banana
cherry
apple
date
banana

Output:

apple
banana
cherry
date

The duplicates (“apple” and “banana”) are removed. The first occurrence of each line is preserved.

Options

Case Insensitive

When enabled, “Apple” and “apple” are treated as duplicates. The first occurrence (whatever its casing) is kept.

Trim Whitespace

Removes leading and trailing spaces from each line before comparison. Lines that differ only by whitespace become duplicates:

"  hello  " and "hello" → treated as same

Remove Empty Lines

Strips all blank lines from the output.

Common Use Cases

• Email lists — remove duplicate addresses before sending
• Data cleaning — deduplicate exported data columns
• Log analysis — find unique error messages or events
• Vocabulary lists — remove repeated words
• CSV processing — deduplicate rows

How to Use Our Duplicate Remover

1. Paste your text with potential duplicates
2. Enable options: case insensitive, trim whitespace, remove empty lines
3. View the deduplicated result immediately
4. Check the stats showing how many duplicates were removed
5. Copy the result

---

Try our free Duplicate Line Remover to deduplicate text instantly.