Done

🧹 Remove Empty & Duplicate Lines

Clean up text instantly — remove blank lines, duplicate lines, trim whitespace, sort, and more. 100% private, runs in your browser.

Input Text
Drop a text file here or click to upload .txt, .csv, .log, .md, .json, and more — max 10 MB
Lines: 0 · Chars: 0 · Words: 0 Size: 0 B
Processing Options
Processing Log
; IndexCraft — Remove Empty & Duplicate Lines
; Browser-based · No upload · 100% private
; ──────────────────────────────────────
; Paste text or upload a file to get started
Settings
Keep Occurrence
Empty Lines
Sort Order
Line Ending
"Keep Occurrence" controls which duplicate copy is kept. "Remove All" removes every occurrence.
Keyboard Shortcuts
Ctrl+↵ Clean text
Alt+C Copy output
Alt+D Download output
Alt+S Swap input ↔ output
Alt+X Clear all
Alt+O Open file
Quick Analysis
Enter text to see analysis
What This Tool Does
Remove Empty Lines — Deletes blank lines or lines containing only whitespace.
Remove Duplicates — Finds repeated lines, keeping first or last occurrence.
Trim Whitespace — Strips leading/trailing spaces and tabs.
Normalize Spaces — Collapses multiple consecutive spaces into one.
Sort Lines — Alphabetically or by length, ascending or descending.
Privacy
🔒 100% Client-Side
All processing happens in your browser. Nothing is sent to any server. Your text never leaves your device.

How to Remove Empty and Duplicate Lines

Step 1 — Paste or upload text: Paste your text directly into the Input area, or click the upload zone to open a .txt , .csv , .log , or any plain text file. Drag-and-drop is also supported. File size limit is 10 MB.
Step 2 — Select options: Toggle Remove Empty Lines , Remove Duplicates , and Trim Whitespace are on by default. Enable Case Insensitive to treat "Hello" and "hello" as duplicates. Enable Normalize Spaces to collapse internal whitespace. Enable Sort Lines for alphabetical output.
Step 3 — Configure settings: In the Settings panel, set which occurrence to keep (first, last, or none), how to handle empty lines (all, consecutive-only, or whitespace-only), sort order (A→Z, Z→A, short→long, long→short, natural), and output line ending (LF, CRLF, or CR).
Step 4 — Clean and export: Click Clean Text (or Ctrl+Enter ) to process. The result appears with statistics. Click Copy to copy to clipboard, Download to save as cleaned-text.txt , or Use as Input to chain another operation.

Common Use Cases

📧

Email List Cleaning

Remove duplicate email addresses from a mailing list export. Enable Case Insensitive to catch duplicates like [email protected] and [email protected] . Remove blank lines that cause import errors.

📊

CSV & Data Files

Deduplicate rows in exported CSV data before importing into a database or CRM. Trim trailing whitespace that causes field-matching failures. The header row is preserved as the first (unique) line.

💻

Code & Config Files

Clean up Python import blocks with repeated imports, remove duplicate CSS rules, tidy YAML or .env config files, or collapse excessive blank lines between code blocks to meet style guide requirements.

📋

Log File Analysis

Remove repeated log entries that inflate file size without adding information. Strip blank lines from application logs before piping them into a parser or analytics tool.

🔤

Word Lists & Dictionaries

Deduplicate and sort word lists for spell-checkers, autocomplete dictionaries, or NLP training datasets. Use Sort Lines with Natural Sort to handle numbered entries correctly.

🌐

URL & Domain Lists

Clean up URL lists for crawlers or redirect rules by removing duplicates. Use Case Insensitive mode since URLs are case-insensitive by convention. Trim trailing slashes via Trim Whitespace.

How This Compares to Other Methods

A feature comparison between this online tool and common alternatives for removing duplicate and empty lines.

Feature This Tool Notepad++ Excel sort -u (CLI) VS Code
No installation needed ✓ ✗ ✗ ✗ ✗
Remove empty lines ✓ ✓ ✗ ✗ ✓
Remove duplicate lines ✓ ✓ ✓ ✓ ✓
Case-insensitive dedup ✓ ✗ ✓ ✓ ✗
Keep first or last occurrence ✓ ✗ ✗ ✗ ✗
Remove all occurrences ✓ ✗ ✗ ✗ ✗
Sort lines (A-Z, length, natural) ✓ ✓ ✓ ✓ ✓
Normalize internal spaces ✓ ✗ ✗ ✗ ✗
Diff view showing changes ✓ ✗ ✗ ✗ ✗
Duplicate details with line numbers ✓ ✗ ✗ ✗ ✗
Preserves original line order ✓ ✓ ✓ ✗ ✓
File upload + download ✓ ✓ ✓ ✓ ✓
Works on any OS / mobile ✓ ✗ ✗ ✗ ✗
100% private (no server upload) ✓ ✓ ✓ ✓ ✓

Frequently Asked Questions

How do I remove duplicate lines from text?
Paste your text into the tool, ensure the Remove Duplicates toggle is on, then click Clean Text . The tool keeps the first occurrence of each unique line and removes subsequent duplicates. In the Settings panel, you can switch to Keep Last to retain the last occurrence, or Remove All to delete every occurrence of any duplicated line.
How do I remove blank lines from text?
Enable the Remove Empty Lines toggle (it is on by default) and click Clean Text . In the Settings panel under "Empty Lines", you can choose: Remove All Empty to delete every blank line; Collapse Consecutive to reduce runs of blank lines to a single blank line; or Only Whitespace-Only to remove only lines that contain spaces or tabs but appear empty.
Is my text sent to a server?
No. All processing runs entirely in your browser using JavaScript. Your text is never sent to any server, stored, or logged. The tool works fully offline once the page has loaded. It is safe to use with confidential documents, passwords, or private data.
Can I remove duplicate lines case-insensitively?
Yes. Enable the Case Insensitive toggle before processing. With this option on, lines that differ only in capitalization — for example [email protected] and [email protected] — are treated as duplicates and the second occurrence is removed. Without it, the comparison is case-sensitive by default.
How do I remove duplicate lines in a CSV file?
Upload your CSV file using the file upload zone or paste the CSV content directly. Enable Remove Duplicates and Trim Whitespace . The header row is automatically preserved as the first (and therefore unique) line. Click Clean Text , then Download to save the deduplicated file as cleaned-text.txt . Rename to .csv after downloading.
What does "Normalize Spaces" do?
Normalize Spaces collapses multiple consecutive spaces or tab characters within a line into a single space. For example, hello   world becomes hello world . This is useful for cleaning text copied from PDFs, web pages, or word processors that introduce irregular spacing. It does not affect leading or trailing spaces — use Trim Whitespace for those.
How do I remove blank lines in Notepad++?
In Notepad++, go to Edit → Line Operations → Remove Empty Lines (or "Remove Empty Lines (Containing Blank Characters)" to also remove whitespace-only lines). For duplicate removal, use the TextFX plugin (TextFX Tools → Sort and remove duplicates). For a faster, no-install alternative with more options (case-insensitive dedup, diff view, sort by length), use this online tool.
How do I remove duplicate lines using the command line?
On Unix/Linux/Mac: sort -u input.txt > output.txt sorts and removes duplicates (changes order). To preserve order: awk '!seen[$0]++' input.txt > output.txt . To also remove blank lines: awk 'NF && !seen[$0]++' input.txt > output.txt . On Windows (PowerShell): Get-Content input.txt | Select-Object -Unique | Where-Object { $_ -ne '' } | Set-Content output.txt . For a browser-based solution with a visual diff, use this tool.
What is the difference between "Keep First", "Keep Last", and "Remove All"?
Keep First (default) preserves the earliest occurrence of each duplicated line and removes all later copies — useful when the original order matters and you want to keep the first instance. Keep Last removes earlier copies and keeps the most recent occurrence — useful when later entries are more up-to-date (e.g. updated records in a log). Remove All deletes every occurrence of any line that appears more than once, leaving only lines that were unique to begin with.