Advanced Git Techniques

Interactive Rebase

Interactive rebase lets you edit, reorder, squash, or drop commits.

git rebase -i HEAD~5

When the editor opens, you’ll see a list of the last five commits. Use the commands:

• pick – keep the commit as‑is
• reword – edit the commit message
• edit – amend the commit
• squash – combine with the previous commit
• drop – remove the commit

After saving and exiting, Git will apply the changes. Resolve any conflicts before continuing with git rebase --continue.

Rewrite History Safely

Never rewrite public history. For private branches, you can use filter-branch or the faster filter-repo tool.

# Remove a file from all history
git filter-repo --path filename.txt --invert-paths

After rewriting, force‑push the branch:

git push --force-with-lease origin my-branch

Use --force-with-lease to protect against overwriting others' work.

Advanced Merge Strategies

Git offers several built‑in strategies. The most common are:

• recursive – default, handles most cases.
• ours – keep current branch’s content.
• theirs – keep incoming branch’s content (via -X theirs).
• octopus – merge more than two branches at once.

Example of a strategy option:

git merge feature-branch -X ours

For complex merges, consider git rerere to record conflict resolutions:

git config --global rerere.enabled true

Managing Submodules

Submodules let you embed other Git repos:

# Add a submodule
git submodule add https://github.com/example/lib.git external/lib
# Clone a repo with submodules
git clone --recurse-submodules https://github.com/user/project.git
# Update submodules
git submodule update --remote --merge

When branching, remember to commit submodule pointer changes.

Custom Git Hooks

Hooks automate tasks. Place executable scripts in .git/hooks.

# .git/hooks/pre-commit (example)
#!/bin/sh
# Prevent committing large files >5 MB
if git diff --cached --name-only | while read f; do
    [ $(stat -c%s "$f") -gt $((5*1024*1024)) ] && echo "$f is too large"
fi; then
    echo "Commit aborted."
    exit 1
fi

Make the hook executable:

chmod +x .git/hooks/pre-commit

Performance Tuning

Speed up large repos with these settings:

# Reduce pack size for faster cloning
git config --global pack.windowMemory "100m"
git config --global pack.packSizeLimit "100m"
# Enable shallow clones when history isn’t needed
git clone --depth 1 https://github.com/user/big-repo.git

Use git gc --aggressive occasionally to prune unreachable objects.

Automation with Git Aliases

Add shortcuts to your global config:

git config --global alias.lg "log --graph --oneline --decorate"
git config --global alias.unstage "reset HEAD --"
git config --global alias.amend "commit --amend --no-edit"

Now you can run git lg to see a concise visual log.