Duplicate Line Remover
Remove repeated lines while keeping the original order.
Use the Duplicate Line Remover tool
What this duplicate line remover does
Duplicate Line Remover takes a list where each line is an item and keeps only the first occurrence of each value. Order is preserved, so the result reads like the original list with repeats deleted rather than a sorted set.
Options let you ignore leading and trailing spaces, compare case-insensitively, and remove empty lines. The tool reports how many lines were removed so you can confirm the change was the one you expected.
Why use it
- Clean a pasted list of email addresses, domains or IDs.
- Deduplicate log output before sharing it.
- Collapse repeated configuration entries.
How to use it
- 1Paste one item per line.
- 2Choose whether to trim whitespace, ignore case and drop blank lines.
- 3Copy the deduplicated list or download it as a text file.
Worked examples
Exact duplicates
Input
alpha beta alpha gamma beta
Output
alpha beta gamma — 2 duplicates removed
Case-insensitive comparison
Input
Example.com example.com
Output
Example.com — 1 duplicate removed when case is ignored
Common mistakes
- Expecting the output to be sorted; this tool preserves first-seen order instead.
- Ignoring hidden trailing spaces, which make two visually identical lines different.
- Deduplicating CSV rows by line when fields contain quoted line breaks.
Frequently asked questions
Which duplicate is kept?
The first occurrence. Later copies are removed, including their surrounding whitespace.
Does it sort the result?
No. Sorting is a separate operation. This tool only removes repeats, which keeps diffs easier to read.
Is the comparison exact?
By default yes, after optional trimming. Enable ignore case if you want Example.com and example.com treated as the same value.