Review a configuration change
Compare before and after text in unified or side-by-side views.
Line-by-Line Text Difference Checker
Line-by-Line Text Difference Checker
Compare original and revised text with an LCS-based line diff in unified or side-by-side views.
Key features
- Computes line changes with a Longest Common Subsequence algorithm.
- Color-codes added and removed lines with their positions and totals.
- Switches between unified diff and original-versus-revised split views.
- Keeps both inputs and the view preference in browser storage.
How to use
- Enter the original text on the left and revised text on the right.
- Inspect added and removed lines in unified or split view.
Examples
Inspect copy edits
Review the count and positions of added and removed lines.
Privacy
Text comparison runs in the browser, and inputs are kept in that browser's local storage.
Requirements
The LCS comparison matrix is capped at 1,000,000 cells for safe browser processing.
Common questions
- Does it compare lines rather than individual characters?
- Yes. A longest-common-subsequence comparison marks added and removed lines with original and modified positions.
- Why can a large comparison be rejected?
- Processing stops when (original line count + 1) × (modified line count + 1) exceeds the 1,000,000-cell matrix cap.
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