Word-Level Diff and Change Stats

Line-level diff tells you which line changed. Word-level diff tells you what inside the line changed.

Example:

LOG_LEVEL=info
LOG_LEVEL=debug

Line-level diff marks the whole line as changed. Word-level diff highlights only info → debug.

When word-level diff helps

Use word-level highlighting when:

• A host name changes slightly (db.internal → db.prod.internal)
• A boolean or number flag flips (false → true)
• A URL path or query parameter changes
• A SQL WHERE clause changes one predicate
• A JSON-looking line is still plain text and you want token-level clarity

Word-level diff is less useful when entire blocks were rewritten or reordered.

Reading change statistics

Good diff tools summarize the result:

• Added lines exist only on the right
• Removed lines exist only on the left
• Changed lines were replaced with a different line at the same position
• Unchanged lines match on both sides

These counts help you decide whether a diff is a small tweak or a large rewrite.

Example summary:

Added: 1 · Removed: 0 · Changed: 3 · Unchanged: 4

That usually means a targeted edit, not a full file replacement.

Key takeaway

Start with line-level diff for structure. Switch to word-level diff when the number of changed lines is small but the actual edit matters.

The Text Diff Checker supports both highlight modes and shows added, removed, changed, and unchanged counts in the status area.