A Detailed Guide to Git Diff Command

Introduction

Git is a popular version control system that allows you to keep track of changes in your software code. One of the most commonly used commands in Git is ‘diff’. The diff command allows you to see the differences between two versions of a file. In this article, we will explain the different uses of the Git diff command, and how you can use it to improve your workflow.

Basic Usage

The basic syntax for the Git diff command is as follows:

git diff [options] [commit] [commit] -- [file]

• options: These are the various command line options that can be used to customize Git diff.
• commit: This option allows you to specify the commit or range of commits that you want to compare. If you don’t specify a commit, Git will compare the current working directory with the most recent commit.
• file: This option specifies the file or directory you want to compare.

For example, to see the changes made in a file named "index.html" since the last commit, you can use the following command:

git diff index.html

Git will then print out a line-by-line comparison of the two versions of the file, highlighting the differences in red and green.

Using Git Diff to Compare Different Branches

Another useful feature of Git diff is the ability to compare different branches. This can be helpful in identifying changes that have been made to a codebase since a particular branch was created.

To compare two branches, you can use the following command:

git diff branch1..branch2

This will compare the differences between branch1 and branch2.

Using Git Diff to View Code Changes Over Time

Git diff can also be used to see how a file or directory has changed over time. This is helpful in understanding the evolution of your codebase and identifying areas where improvements can be made.

To view the changes made to a file over time, you can use the following command:

git log -p filename

This will show a log of all the commits that have been made to the file, along with the changes made in each commit.

Customizing Git Diff Output

Git diff also offers a variety of options that can be used to customize the output. These options allow you to change the format of the output and highlight differences in different ways.

Some commonly used options include:

• --color: Shows the output in color.
• --word-diff: Shows only the changed words instead of entire lines.
• --word-diff-regex: Allows you to specify a regular expression to use for word diff.

For example, to view the word-level changes made in a file since a particular commit, you can use the following command:

git diff --color --word-diff=porcelain commitid filename

This will show the word-level changes made in the file, highlighted in red and green.

Conclusion

In conclusion, Git diff is a powerful tool that can be used to identify changes in your codebase, compare different versions of a file, and view the evolution of your code over time. By mastering the various options and uses of Git diff, you can streamline your workflow and become a more efficient coder.