OGG… How do I check unstaged differences with the latest commit?

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 diff

This 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 --staged git 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_tool

For example, if you prefer to vscode,

git config --global diff.tool vscode

To check if you successfully configure difftool editor,

git config -l

then, 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=vimdiff