A two-column diff of an nginx config, two changed lines tinted red on the left and green on the right with the edited words highlighted, and a fold marker for 12 unchanged lines

Guides11 Nov 2026 · 4 min read

How to compare two versions of a text, config file or code, and read the diff

“What changed?” is hard to answer by eye. Here’s how a diff works, when to compare line by line or word by word, and how to read the results in the Diff Checker and Text Compare.

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