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### Showing Differences in Their Context

Usually, when you are looking at the differences between files, you will also want to see the parts of the files near the lines that differ, to help you understand exactly what has changed. These nearby parts of the files are called the context.

GNU `diff` provides two output formats that show context around the differing lines: context format and unified format. It can optionally show in which function or section of the file the differing lines are found.

If you are distributing new versions of files to other people in the form of `diff` output, you should use one of the output formats that show context so that they can apply the diffs even if they have made small changes of their own to the files. `patch` can apply the diffs in this case by searching in the files for the lines of context around the differing lines; if those lines are actually a few lines away from where the diff says they are, `patch` can adjust the line numbers accordingly and still apply the diff correctly.

- Context Format: An output format that shows surrounding lines.
- Unified Format: A more compact output format that shows context.
- Sections: Showing which sections of the files differences are in.
- Alternate Names: Showing alternate file names in context headers.