Git Quick Tutorial
Pikicast R&D
Jack Pham

Git Commands
Setting up a repository init, clone, config
Saving changes add, commit
Inspecting a repository status, log
Navigate through commit and branch checkout
Undo changes checkout, revert, reset, clean
Rewriting history commit —ammend, rebase (rebase -i), reflog
Syncing remote, fetch, pull, push
Branching branch, checkout, merge
* Need to use with caution, should never be done on public(share) target

Setup a repository and
start working
init
clone

git vs svn

Git init
git init
git init --bare
git clone

Saving changes
add
commit

Git repository local

Working Directory Stage Area
File status
git add
git add
git commit
git rm
Tracked

Common Git Routine (Local)
- Edit-Stage-Commit
$vim hello.js
# Edit
$ git add hello.js
$ git commit
# Edit commit message
- Edit-Stage-Commit-Amend
# Edit hello.js
$ git add hello.js
$ git commit --amend
# Edit commit message
** Don’t amend commit that you already push to public repository

Viewing old commits
log
checkout

View log
$ git log
$ git log -n <limit>
$ git log --oneline
$ git log --stat
$ git log -p
$ git log --author=“<patterns>”
$ git log <file>
$ git log --graph --decorate --oneline
$ git log --grep=“<patterns>”

git checkout branch
git checkout master git checkout feature

git checkout commit
git checkout master
git checkout 81abc12
** Don’t commit your work on a detach head

Checkout options
git checkout <branch>
git checkout <commit>
git checkout <commit> <file>
Example:
git checkout master
git checkout a12ebd3
git checkout a12ebd3 hello.js

Undoing changes
checkout
revert
reset

git checkout to undo
git checkout a1e8fb5 # modify files
git add <file>
git commit

git revert <commit>
git revert abcd12ef
Before revert
After revert
abcd12ef
- The git revert command undoes a committed snapshot.
- Undo the changes introduced by the commit
- Appends a new commit with the resulting content.
- git revert doesn't alter history

git reset
abcd12ef abcd12ef
Before reset
After reset
- Variation:
- git reset <file> : remove from staging area
- git reset : reset branch to most recent commit (soft)
- git reset ——hard
- git reset <commit>
- git reset ——hard <commit>
- git revert is “safe” way to undo
- git reset “dangerous” to undo
** Don’t reset if you’ve already pushed to shared repository

revert vs reset
- Don’t alter history
- Safe way to undo but generate
more commit
- For undo shared/public commits
- Alter history
- unsafe way to undo
shared/public commits
- Cleaner history
- For undo private (non-public)
commits

Rewriting History
commit --amend
reflog
rebase

git commit --amend
- Modify last commit
- Replace last commit entirely
- Use to fix last commit (which hasn't pushed
to share repo)
- Variation
- git commit --amend
- git commit --amend --no-edit
** Don’t amend commit that you already push to public repository

git rebase <base>
- Rebasing is the process of moving a
branch to a new base commit.
- Maintain linear history
git rebase
git merge

git reflog
- What to do if you accidentally
- git reset --hard
- Reflog contain log of activity you perform

Remote synchronise
and branching
remote
pull
fetch
push
branch
merge

git remote
git remote
git remote -v
git remote add <name> <url>
git remote rm <name>
git remote rename <oldname> <new-name>

git fetch
- Download commits from remote but not merge to
local
- Give you opportunity to review
- Merge or rebase after review
git fetch <remote>
git fetch <remote> <branch>

git pull
git fetch
git merge
git pull = git fetch + git merge
git pull --rebase = git fetch + git rebase
- Download commits from remote and
merge (or rebase) to local branch

git push
transfer commits from your local
repository to a remote repo.
git push <remote>
git push <remote> —force
git push <remote> -all
git push <remote> --tags
** Do not use the --force flag unless you’re absolutely sure you know
what you’re doing.

git branch
Represented by a pointer (branch tip)
git branch
git branch <branch>
git branch -d <branch>
git branch -D <branch>
git branch -m <branch>

git merge
Putting forked history back together
git branch -m <branch>
git branch --no-ff <branch>
fast-forward
(git does this whenever possible)
non-fast-forward (3-ways merge)
(probably after rebase)

Cleaner history
- Private branch: rebase & fast-forward merge
- Share: 3-way merge
- Atomic commit and meaningful message
- Good naming convention

Staying out of troubles
- Don’t amend commit that you already shared
repository
- Don’t commit your work on a detached head
- Don’t reset if you’ve already pushed to shared
repository
- Don’t use the ‘push --force’ flag unless you’re
absolutely sure you know what you’re doing.