Comparing and Merging Files

This file documents the the GNU diff, diff3, sdiff, and cmp commands for showing the differences between text files and the patch command for using their output to update files.

This is Edition 1.2, for diff 2.4 and patch 2.1.

Overview

Preliminary information.

1. What Comparison Means		What file comparison means.
2. diff Output Formats		Formats for difference reports.
3. Comparing Directories		Comparing files and directories.
4. Making diff Output Prettier		Making diff output prettier.
5. diff Performance Tradeoffs		Making diff smarter or faster.
6. Comparing Three Files		Formats for three-way difference reports.

7. Merging From a Common Ancestor		Merging from a common ancestor.
8. Interactive Merging with sdiff		Interactive merging with sdiff.
9. Merging with patch		Using patch to change old files into new ones.
10. Tips for Making Patch Distributions		Tips for making patch distributions.

11. Invoking cmp		How to run cmp and a summary of its options.
12. Invoking diff		How to run diff and a summary of its options.
13. Invoking diff3		How to run diff3 and a summary of its options.
14. Invoking patch		How to run patch and a summary of its options.
15. Invoking sdiff		How to run sdiff and a summary of its options.

16. Incomplete Lines		Lines that lack trailing newlines.
17. Future Projects		If you think you've found a bug or other shortcoming.

Concept Index

Index of concepts.