Remove Duplicate Lines

What Remove Duplicate Lines does

Deduplicate a line-based list while controlling case, whitespace and original order, with the cleaned result available to copy.

Worked example

How the result is produced

Each line is converted to a comparison key according to the selected case and whitespace rules. The first occurrence of each key is retained unless the chosen mode states otherwise.

Useful workflows

• Clean exported keyword or email lists
• Remove repeated IDs before an import
• Deduplicate test data while preserving its first-seen order

Important limits

• Case-insensitive mode can merge identifiers that are distinct in a technical system.
• Hidden Unicode spaces or normalization differences may look identical.
• Review the result before replacing the source list.

Frequently asked questions

Can I preserve the original order?

Yes. Use the option that keeps the first occurrence rather than sorting the result.

Are blank lines duplicates?

That depends on the blank-line and whitespace options; verify the preview for your chosen settings.

Can I keep the first occurrence order?

Use the order-preserving option when sequence matters; sorting before deduplication changes the original order.