Find duplicate line groups with exact source positions and original values. Choose line, case and whitespace policies and export a complete review report.
Specialist tool for Text AnalysisLive, copy-ready outputFocused single-task workflowPrivate in your browser
Use this result well
A quick decision brief for this specific tool
Inputs that matter
Text source
Output to expect
Complete JSON report
How it works
A dedicated interactive panel for this data format or operation
Start with the included valid sample, then replace it with your own input.
Review errors and compare the output before replacing source data.
Choose your path
Built around the job you need to finish
Find repeated line comparison keys with explicit boundary, normalization, empty-record and case policies while retaining original lines and all occurrence positions.
Log reviewer
Find repeated literal records including special object-key text.
Analyze repeated __proto__, constructor and ordinary log lines; inspect occurrence counts and line numbers.
Literal text is counted safely and each occurrence remains traceable.
Data-cleaning analyst
Decide whether case, edge spaces or canonical forms should be equivalent.
Compare exact mode with ASCII edge trim, lowercase and NFC; review original variants.
Comparison changes never erase evidence or automatically delete rows.
Mobile file auditor
Handle CRLF, lone CR, terminal records and large results predictably.
Import a BOM/CRLF fixture, choose delimiter/final-empty policy, page groups and export all positions.
Can explain record totals and retain every original occurrence.
Authoritative checks for this tool
Outputs and checklists are planning aids. Review the linked current authorities and the records, terms, instructions, and requirements that apply to your exact situation before a consequential decision.
Default delimiters are CRLF, LF and lone CR. Unicode mode additionally recognizes NEL, LS and PS. A final delimiter can add an explicitly included empty record.
Comparison keys
Optional ASCII edge trim, NFC and default lowercase affect keys only. Empty-key exclusion runs after those choices; BOM and non-ASCII spaces are preserved.
Auditable groups
Each group retains all original values and one-based line numbers. Group count, total repeated occurrences and excess occurrences are distinct metrics.
Updated: August 2026
Example Scenarios
Find repeated literal records including special object-key text. Analyze repeated __proto__, constructor and ordinary log lines; inspect occurrence counts and line numbers.
Decide whether case, edge spaces or canonical forms should be equivalent. Compare exact mode with ASCII edge trim, lowercase and NFC; review original variants.
Handle CRLF, lone CR, terminal records and large results predictably. Import a BOM/CRLF fixture, choose delimiter/final-empty policy, page groups and export all positions.
Common Mistakes to Avoid
✕
Confusing duplicate groups with extra records
✓
Three identical lines form one group with three occurrences and two extras after the first.
✕
Treating normalized matches as identical source bytes
✓
Inspect the original values; normalization and lowercase can merge distinct strings.
FAQ
No. It produces an inspection report. Keep the original source and decide separately which records to remove.
Including the final empty record adds one record after the last delimiter. Choose omission explicitly if that matches your file convention.
Not by default. ASCII edge trim and default lowercase are explicit comparison options, not source edits.
No. It analyzes line records, not CSV fields or quoted multiline rows. Use a CSV parser for that task.
Yes. The complete JSON report includes every selected group, its original lines and all one-based source positions, beyond the preview limit.
About Duplicate Line Finder
Find repeated line comparison keys with explicit boundary, normalization, empty-record and case policies while retaining original lines and all occurrence positions.