Git useful commands

branch.sh

# create new branch
git branch <branch name>

# create new branch and checkout to it
git checkout -b <branch name>

# upload new branch to remote
git push origin <branch name>

# delete local branch
git branch -d <branch name>

# delete remote branch
git push origin :<branch name>

# show branch mapping local/remote
git remote show origin

# remove stale remote branches
git remote prune origin

# remove merged branches
git branch --merged | egrep -v "(^\*|master|develop)" | xargs git branch -d

cherry-pick.sh

# merge a specific commit from a branch to another
git checkout <target branch>

git cherry-pick <hash>

# --edit: changes the message
# --no-commit <hash1> <hash2>: pulls in changes and stages them, but does not commit
# -x: adds source SHA to commit message
# --signoff: adds current users's name to commit message

config.sh

# change CRLF to LF on commit - Unix-like systems
git config --global core.autocrlf input

# change LF to CRLF on checkout and converts back on commit
git config --global core.autocrlf true

diff.sh

# difference between HEAD and previous commit
git diff HEAD^

# difference between HEAD and 5 commits ago 
git diff HEAD~5

# difference between HEAD and specific commit
git diff <hash>

# difference between 2 commits
git diff <hash> <another hash>

# difference between two branches
git diff <branch> <another branch>

# difference between two tagged commits
git diff <tag> <another tag>

filter-branch.sh

# purging history
# make a backup before changing history
git clone <repo> <new repo>

# for each commit in the specified branch, apply filters to the snapshot, and create a new commit

# filter for rewriting the tree and its contents
git filter-branch --tree-filter <command>

# remove "passwords.txt" from project root
git filter-branch --tree-filter "rm -f passwords.txt"

# remove video files from any directory
git filter-branch --tree-filter "find . -name

# filter for rewriting the index - operates on staging area
git filter-branch --index-filter <command>

# remove "passwords.txt" form staging area
git filter-branch --index-filter "git rm --cached --ignore-unmatch passwords.txt"

# ome filters will generate empty commits that leave the tree untouched. 
# this option instructs git filter-branch to remove such commits if they have exactly one or zero non-pruned parents
git filter-branch -f --prune-empty -- --all

log.sh

# Log options
# %ad - Author date
# %an - Author name
# %h - SHA hash
# %s - Subject
# %d - Ref names

git log --pretty=format:"%h %ad - %s [%an]"

# filter logs by date range
git log --since=1.month.ago --until=2.weeks.ago

rebase.sh

# branch to be rebased
git checkout <branch name>

# target is the branch that will be used as base for rebasing
git rebase <target branch>

# interactive rebase - option -i or --interactive
git rebase -i <target branch>

# p, pick - use commit
# r, reword - use commit, but edit its message
# e, edit - use commit, but stop for amending
# s, squash - use commit, but meld it into previous commit
# f, fixup - like 'squash', but discard this commit's log message
# x, exec - run command (the rest of the line using shell)

reflog.sh

# reference logs, or "reflogs", record when the tips of branches and other references were updated in the local repository

git reflog <subcommand> <options>

# reset based on reflog entry
git reset --hard HEAD@{#}

reset.sh

# reset basically moves the HEAD pointer to another commit behind it
# and updates Index and Working Directory, depending on the used flag

# undo last commit and add files back to staging area -> undo `git commit`
# Step 1: `--soft` simply changes the HEAD pointer, no changes on the `Index` or `Working Directory`,
# which is the reason why the files show in the stagging area (Files in HEAD != Files in Index)
git reset --soft HEAD~

# undo last commit and unstage changes -> undo `git commit` and `git add`
# Step 2: `--mixed` (default) will change the commit HEAD points to 
# and update the `Index` with the contents of whatever `HEAD` now points to so they're the same.
git reset [--mixed] HEAD~

# undo last commit and discard files -> undo `git commit`, `git add`, and discard changes
# Step 3: `--hard` will, besides updating the HEAD and updating the `Index`,
# update the `Working Directory` with whatever is in the updated `Index`
# this flag is the most dangerous one for reset, once it overwrites the content of the `Working Directory`
git reset --hard HEAD~

# reset with a path -> undo `git add`
# if a path is provided, reset will skip the Step 1, once we'll be working with subsets of a commit
# and apply the other 2 steps, updating `Index` with whatever is in `HEAD`.
# it does not accept `--hard` -> use `git checkout <hash> file.txt` instead
git reset [--mixed] [HEAD] file.txt

# if a specific commit hash is given, reset will update `Index` with the content of `file.txt` existing in that commit
git reset [--mixed] <hash> file.txt

# replace message from and/or add more changed to last commit
git commit --amend -m "<new message>" 

# Notation:
# Both ~ and ^ on their own refer to the parent of the commit (~~ and ^^ both refer to the grandparent commit, etc.) 
# But they differ in meaning when they are used with numbers:
#     * ~2 means up two levels in the hierarchy, via the first parent if a commit has more than one parent
#     * ^2 means the second parent where a commit has more than one parent (i.e. because it's a merge)

stash.sh

# store un-commited files (needs to be added to staging area - only gets tracked files)
git stash [save | push]

# --include-untracked: all untracked files are also stashed
# --all:  ignored files are stashed in addition to the untracked files
# --keep-index: stashed files and leaves them in the staging area - same as git stash; git stash apply

# restore previous stash entry - #0 is default
git stash apply [stash@{#}]

#list stashed items
git stash list --stat

# remove stash entry
git stash drop [stash@{#}]

# permorm apply followed by drop - git stash apply; git stash drop
git stash pop

# show the changes recorded in the stash entry as a diff between the stashed contents and the commit back when the stash entry was first created
git stash show [stash@{#}]

# --patch: shows file's diffs

# check a new branch out automatically and drops the stash entry
git stash branch <branch name> [stash@{#}]

# remove all stash entries
git stash clear

submodules.sh

# add a repo as a internal submodule
git submodule add <url>

# when changing submodules code, checkout a branch first

# when cloning a repo with submodules do:
git submodule init

git submodule update

# merge commits with no branch
git checkout <branch>
git merge <hash> # no-branch commit's hash

# pushing submodules
# first push /submodule repo
# then push parent repo

# abort a push if submodules haven't been pushed
git push --recurse-submodules=check

# psuh parent and submodule commits
git push --recurse-submodules=on-demand

# create an alias
git config alias.pushall "push --recurse-submodules=on-demand"

tag.sh

# add tag
git tag <tag name>

# upload tags to remote
git push --tags

# list tags
git tag -l

# delete local tag '<tag name>'
git tag -d <tag name>

# delete remote tag '<tag name>' 
git push origin :refs/tags/<tag name>

# alternative approach
git push --delete origin <tag name>
git tag -d <tag name>

# delete all local tags
git tag -l | xargs git tag -d