Remove Duplicate Lines
This tool removes repeated lines from a block of text and keeps only one occurrence of each unique line. It is useful when text contains accidental duplication, such as copied lists, logs, datasets, or manually edited content where the same line appears multiple times.
Instead of manually scanning and deleting duplicates, the tool applies clear and predictable rules to determine which lines are considered identical and produces a cleaned version of the text instantly.
How Duplicate Detection Works
The tool processes your text line by line and compares each line against the ones already seen. When a duplicate is detected, the extra occurrence is removed and only the first instance is retained.
Additional options allow you to control how strict the comparison should be. For example, two lines that differ only in letter case or surrounding spaces can be treated as the same line if those differences are ignored.
Cleanup Options Explained
You can fine-tune how duplicates are detected and how the final output is organized using the following options.
- Ignore case — Treats lines with different letter casing as identical, such as Apple and apple.
- Ignore whitespace — Trims leading and trailing spaces before comparison, preventing spacing differences from creating false uniqueness.
- Sort lines alphabetically — Orders the remaining unique lines alphabetically after duplicates are removed.
Examples and Edge Cases
When working with lists copied from spreadsheets, logs, or scraped content, the same entry may appear multiple times with minor variations. Ignoring case and whitespace helps treat these as duplicates without requiring exact character-by-character matches.
If sorting is enabled, the original order of lines is no longer preserved. This can be useful for readability or comparison, but it may not be desirable when line order carries meaning.
Who Should Use This Tool
Removing duplicate lines is helpful whenever text needs to be unique, compact, and easier to reason about.
- Cleaning lists or datasets before analysis
- Removing repeated entries from copied content
- Normalizing logs, exports, or configuration files
- Preparing unique values for further processing
Related Concepts
Duplicate removal is often part of a broader text-cleanup or preparation workflow.
- Removing extra spaces before comparison
- Sorting text lines for easier review
- Counting words or characters after cleanup
If your text contains inconsistent spacing, you may want to clean it first using Remove Extra Spaces, or reorder the final output with Sort Text Lines.