Git Advanced Operations Skill

This skill provides comprehensive guidance on advanced git operations, sophisticated rebase strategies, commit surgery techniques, and complex history manipulation for experienced git users.

When to Use

Activate this skill when:

• Performing complex interactive rebases
• Rewriting commit history
• Splitting or combining commits
• Advanced merge strategies
• Cherry-picking across branches
• Commit message editing in history
• Author information changes
• Complex conflict resolution

Interactive Rebase Strategies

Basic Interactive Rebase

# Rebase last 5 commits
git rebase -i HEAD~5

# Rebase from specific commit
git rebase -i abc123^

# Rebase entire branch
git rebase -i main

Rebase Commands

# Interactive rebase editor commands:
# p, pick = use commit
# r, reword = use commit, but edit commit message
# e, edit = use commit, but stop for amending
# s, squash = use commit, but meld into previous commit
# f, fixup = like squash, but discard commit message
# x, exec = run command (the rest of the line) using shell
# d, drop = remove commit

Squashing Commits

# Example: Squash last 3 commits
git rebase -i HEAD~3

# In editor:
pick abc123 feat: add user authentication
squash def456 fix: resolve login bug
squash ghi789 style: format code

# Squash all commits in feature branch
git rebase -i main
# Mark all except first as 'squash'

Fixup Workflow

# Create fixup commit automatically
git commit --fixup=abc123

# Autosquash during rebase
git rebase -i --autosquash main

# Set autosquash as default
git config --global rebase.autosquash true

# Example workflow:
git log --oneline -5
# abc123 feat: add authentication
# def456 feat: add authorization
git commit --fixup=abc123
git rebase -i --autosquash HEAD~3

Reordering Commits

# Interactive rebase
git rebase -i HEAD~5

# In editor, change order:
pick def456 feat: add database migration
pick abc123 feat: add user model
pick ghi789 feat: add API endpoints

# Reorder by moving lines:
pick abc123 feat: add user model
pick def456 feat: add database migration
pick ghi789 feat: add API endpoints

Splitting Commits

# Start interactive rebase
git rebase -i HEAD~3

# Mark commit to split with 'edit'
edit abc123 feat: add user and role features

# When rebase stops:
git reset HEAD^

# Stage and commit parts separately
git add user.go
git commit -m "feat: add user management"

git add role.go
git commit -m "feat: add role management"

# Continue rebase
git rebase --continue

Editing Old Commits

# Start interactive rebase
git rebase -i HEAD~5

# Mark commit with 'edit'
edit abc123 feat: add authentication

# When rebase stops, make changes
git add modified-file.go
git commit --amend --no-edit

# Or change commit message
git commit --amend

# Continue rebase
git rebase --continue

Commit Surgery

Amending Commits

# Amend last commit (add changes)
git add forgotten-file.go
git commit --amend --no-edit

# Amend commit message
git commit --amend -m "fix: correct typo in feature"

# Amend author information
git commit --amend --author="John Doe <[email protected]>"

# Amend date
git commit --amend --date="2024-03-15 10:30:00"

Changing Commit Messages

# Change last commit message
git commit --amend

# Change older commit messages
git rebase -i HEAD~5
# Mark commits with 'reword'

# Change commit message without opening editor
git commit --amend -m "new message" --no-edit

Changing Multiple Authors

# Filter-branch (legacy method, use filter-repo instead)
git filter-branch --env-filter '
if [ "$GIT_COMMITTER_EMAIL" = "[email protected]" ]; then
    export GIT_COMMITTER_NAME="New Name"
    export GIT_COMMITTER_EMAIL="[email protected]"
fi
if [ "$GIT_AUTHOR_EMAIL" = "[email protected]" ]; then
    export GIT_AUTHOR_NAME="New Name"
    export GIT_AUTHOR_EMAIL="[email protected]"
fi
' --tag-name-filter cat -- --branches --tags

# Modern method with git-filter-repo
git filter-repo --email-callback '
    return email.replace(b"[email protected]", b"[email protected]")
'

Removing Files from History

# Remove file from all history
git filter-branch --tree-filter 'rm -f passwords.txt' HEAD

# Better performance with index-filter
git filter-branch --index-filter 'git rm --cached --ignore-unmatch passwords.txt' HEAD

# Modern method with git-filter-repo (recommended)
git filter-repo --path passwords.txt --invert-paths

# Remove large files
git filter-repo --strip-blobs-bigger-than 10M

BFG Repo-Cleaner

# Install BFG
# brew install bfg (macOS)
# apt-get install bfg (Ubuntu)

# Remove files by name
bfg --delete-files passwords.txt

# Remove large files
bfg --strip-blobs-bigger-than 50M

# Replace passwords in history
bfg --replace-text passwords.txt

# After BFG cleanup
git reflog expire --expire=now --all
git gc --prune=now --aggressive

Advanced Cherry-Picking

Basic Cherry-Pick

# Cherry-pick single commit
git cherry-pick abc123

# Cherry-pick multiple commits
git cherry-pick abc123 def456 ghi789

# Cherry-pick range of commits
git cherry-pick abc123..ghi789

# Cherry-pick without committing (stage only)
git cherry-pick -n abc123

Cherry-Pick with Conflicts

# When conflicts occur
git cherry-pick abc123
# CONFLICT: resolve conflicts

# After resolving conflicts
git add resolved-file.go
git cherry-pick --continue

# Or abort cherry-pick
git cherry-pick --abort

# Skip current commit
git cherry-pick --skip

Cherry-Pick Options

# Edit commit message during cherry-pick
git cherry-pick -e abc123

# Sign-off cherry-picked commit
git cherry-pick -s abc123

# Keep original author date
git cherry-pick --ff abc123

# Apply changes without commit attribution
git cherry-pick -n abc123
git commit --author="New Author <[email protected]>"

Mainline Selection for Merge Commits

# Cherry-pick merge commit (specify parent)
git cherry-pick -m 1 abc123

# -m 1 = use first parent (main branch)
# -m 2 = use second parent (merged branch)

# Example workflow:
git log --graph --oneline
#   *   abc123 Merge pull request #123
#   |\
#   | * def456 feat: feature commit
#   * | ghi789 fix: main branch commit

# To cherry-pick the merge keeping main branch changes:
git cherry-pick -m 1 abc123

Advanced Merging

Merge Strategies

# Recursive merge (default)
git merge -s recursive branch-name

# Ours (keep our changes on conflict)
git merge -s ours branch-name

# Theirs (keep their changes on conflict)
git merge -s theirs branch-name

# Octopus (merge 3+ branches)