GNU Diffutils includes diff and cmp, but they answer different questions. diff normally describes text changes line by line, making it useful for reviewing a configuration edit. cmp compares two files at the byte level and normally identifies the first differing byte and line, or reports that one file ends earlier.

Choose diff when a person needs to understand what changed in readable text. Its usual handling of binary files may only report that they differ, not explain a document or image visually. A textual change report is therefore not a substitute for opening an exported presentation or checking its layout in the receiving application.

Choose cmp when the question is whether two local file contents match exactly. The GNU manual documents exit status 0 for no differences, 1 for differences and 2 for trouble. A script must not collapse the last two outcomes: unreadable input is not a completed comparison that found a normal change.

Neither command establishes who supplied a file or whether its contents are trustworthy. Compare copies you can read, keep originals unchanged and use authenticated publisher verification separately for downloaded software. Verdict: diff for explaining text edits, cmp for byte identity. This is a manual-based comparison, not a speed test or affiliate recommendation.