Problem
After committing changes to files in your working repository, you continue working on further developments. Then, you notice that you’ve accidentally made some errors in certain git-tracked files, and the class is not working.
You want to check what changes you’ve made compared to the latest commit, but you’re not sure how to do it. It would also be helpful to view the differences in an editor.
Solution 1: Using git diff
git diff allows you to inspect changes in your code, from minor edits to major branch comparisons.
▶ Key Takeaways
| Commands | Explaination |
|---|---|
git diff |
Check unstaged changes with HEAD |
git diff --staged |
Check staged changes with HEAD |
git diff <commit1> <commit2> |
Compare two specific commits |
git diff main feature-branch |
Compare branches |
git diff HEAD -- <file/directory-path> |
Check single file/directory changes with HEAD |
git diff --stat |
Shows a summary of changes for each file, such as how many lines were added and deleted |
▶ Viewing Changes in the Working Directory
To see all changes in your working directory that haven’t been staged,
git diffThis command shows the differences between your working directory and the last commit in your terminal display.
If you want to see staged changes with your latest commit,
git diff --staged▶ Comparing with a Specific Commit
To see differences between your current state and a specific commit,
## (1) Compared with latest commit
git diff
git diff HEAD
## (2) Compared with specific commit
git diff <commit-hash>
## (3) Comparing two specific commits
git diff <commit-hash1> <commit-hash2>
## (4) Comparing the HEAD with the HEAD~1
git diff HEAD~1 HEAD▶ Comparing Branches
You can also use git diff to compare different branches.
git diff main feature-branch▶ Shows a summary of changes for each file
When you want to see a summary of changes for each file, such as how many lines were added and deleted, use git diff --stat. If you want to compare the current branch with gh-pages branch in .github/ directory,
% git diff --stat gh-pages .github/
.github/ISSUE_TEMPLATE/fix_documentation.yml | 39 +++++++++++++++++++++++++++++++++++++++
.github/ISSUE_TEMPLATE/fix_typos.yml | 32 ++++++++++++++++++++++++++++++++
.github/pull_request_template.md | 25 +++++++++++++++++++++++++
.github/workflows/publish.yml | 26 ++++++++++++++++++++++++++
.github/workflows/rss-to-twitter.yml | 20 ++++++++++++++++++++
5 files changed, 142 insertions(+)The number shows how many lines are modified for each files.
Solution 2: Using git difftool
git difftool is a Git command that lets you view differences between versions of files in an external, graphical diff tool. It’s particularly useful if you want to view the differences in an editor.
The syntax of git difftool is similar to git diff. For example,
git difftool commands |
git diff commands |
|---|---|
git difftool |
git diff |
git difftool --stagedgit difftool --cached |
git diff --staged |
git difftool <commit1> <commit2> |
git diff <commit1> <commit2> |
git difftool main feature-branch |
git diff main feature-branch |
git difftool HEAD -- <file/directory-path> |
git diff HEAD -- <file/directory-path> |
▶ Choosing an editor
You can set your preferred tool globally so it opens automatically each time you use the command. The setup syntax is
git config --global diff.tool your_preferred_toolFor example, if you prefer to vscode,
git config --global diff.tool vscodeTo check if you successfully configure difftool editor,
git config -lthen, you can check what editor is you default git difftool editor.
▶ Choosing an editor temporarily
If you temporarily show the diff in vimdiff,
git difftool HEAD~1 HEAD --tool=vimdiffAppendix: Role of -- in Git
In git command, -- is a seperator between options and paths. It is useful when a name could be ambiguous—e.g., if a branch or tag has the same name as a file.
If the path (file or directory) does not conflict with a branch or tag name, Git automatically treats it as a path.
Example 1
git diff feature -- file.txtIn the above command, feature could be interpreted as either a branch or a file. Using -- explicitly tells Git that anything after it is a path, not a branch or option.
Example 2
git diff README.mdGit sees that README.md is not a branch or tag, so it is interpreted as a file path. Therefore, the command works correctly even without --.