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Sort lines alphabetically or numerically in any text list. Free online line sorter for cleaning datasets, organizing names, and preparing sorted output.
Add line numbers to text automatically. Prefix each row with sequential indices for code snippets, documentation, legal excerpts, and shared references.
Strip blank and whitespace-only lines from pasted text. Tighten prose, config files, and copied data for cleaner exports without manual editing.
Uses a Set data structure to track seen lines. First occurrence is kept; subsequent duplicates are removed. Order is preserved (stable deduplication). O(n) time complexity.
For each line: if not in seen_set → output line, add to set; else → skipBefore comparison, lines can be normalized: trim whitespace, convert case, ignore leading/trailing characters. This catches near-duplicates that differ only in formatting.
Updated: July 2026
Remove repeated error messages from a verbose log, keeping first occurrence of each.
→ Deduplicated log with unique entries only, preserving chronological order
Combine two mailing lists and remove any email that appears more than once.
→ Unique email list with duplicates removed regardless of case
Default deduplication keeps first occurrence. If you need the last occurrence (e.g., latest config value), reverse the list, deduplicate, then reverse again.
Lines with invisible trailing spaces or tabs look identical but are different strings. Always trim before comparison unless whitespace is semantically significant.
Remove duplicate lines from text while keeping unique rows. Clean email lists, URLs, log entries, and data files quickly with this free online tool. It applies the deduplication algorithm (For each line: if not in seen_set → output line, add to set; else → skip). For example: clean a log file — Remove repeated error messages from a verbose log, keeping first occurrence of each.