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diff Command in Linux

diff Command in Linux

By Team Scaler
2 mins read
Last updated: 31 Aug 2023
145 views
Topics Covered

Overview

The diff command in Linux is a powerful utility that compares files or directories and displays the differences between them. It is commonly used by developers to identify changes in source code, configuration files, or documentation. This article provides an overview of the diff command, its syntax, and examples of its usage.

Linux diff Command Syntax

The syntax for the diff command is as follows:

Where:

  • OPTION: One or more options that modify the behavior of the diff command. These options can control how the differences are displayed or specify which files to compare.
  • FILES: Two files or directories to be compared by the diff command.

diff Command Options:

  • -c: Display output in context format, showing several lines of context around the differences.
  • -u: Display output in unified format, which is similar to context format but more compact.
  • -r: Recursively compare subdirectories when comparing directories.
  • -i: Ignore case differences when comparing files.

Example Usages

  • Compare two text files and display the differences.:

    Output:

    Explanation: The diff command will compare the contents of file1.txt and file2.txt and show the differences between them line by line.

  • Compare two directories and display the differences in a unified format.:

    Output:

    Explanation: The diff command will compare the contents of dir1 and dir2 and show the differences between their files in a unified format.

Tips

  • Use the 'patch' command to apply the differences generated by the 'diff' command to a file.

  • You can pipe the output of 'diff' to other commands like 'less' for easier viewing.

Advanced Use Cases of diff Command in Linux

  • Compare two files ignoring case differences.:

    Output:

    Explanation: The diff command will compare the contents of file1.txt and file2.txt, ignoring case differences, and show the differences between them line by line.

  • Compare two directories recursively.:

    Output:

    Explanation: The diff command will compare the contents of dir1 and dir2, including their subdirectories, and show the differences between their files.

  • Compare two files and show the differences in context format.:

    Output:

    Explanation: The diff command will compare the contents of file1.txt and file2.txt and show the differences between them in context format, which includes several lines of context around the differences.

Conclusion

  • The diff command is a powerful utility for comparing files and directories.

  • It offers various options to customize the output format and comparison behavior.

  • It is widely used by developers and system administrators to identify changes in files or directories.