Get the code: LearnGit.txt
Git is a distributed version control and source code management system.
It does this through a series of snapshots of your project, and it works with those snapshots to provide you with functionality to version and manage your source code.
Version control is a system that records changes to a file(s), over time.
A set of files, directories, historical records, commits, and heads. Imagine it as a source code data structure, with the attribute that each source code “element” gives you access to its revision history, among other things.
A git repository is comprised of the .git directory & working tree.
The .git directory contains all the configurations, logs, branches, HEAD, and more. Detailed List.
This is basically the directories and files in your repository. It is often referred to as your working directory.
The Index is the staging area in git. It’s basically a layer that separates your working tree from the Git repository. This gives developers more power over what gets sent to the Git repository.
A git commit is a snapshot of a set of changes, or manipulations to your Working Tree. For example, if you added 5 files, and removed 2 others, these changes will be contained in a commit (or snapshot). This commit can then be pushed to other repositories, or not!
A branch is essentially a pointer to the last commit you made. As you go on committing, this pointer will automatically update to point to the latest commit.
A tag is a mark on specific point in history. Typically people use this functionality to mark release points (v1.0, and so on).
HEAD is a pointer that points to the current branch. A repository only has 1 active HEAD. head is a pointer that points to any commit. A repository can have any number of heads.
Create an empty Git repository. The Git repository’s settings, stored information, and more is stored in a directory (a folder) named “.git”.
$ git init
To configure settings. Whether it be for the repository, the system itself,
or global configurations ( global config file is ~/.gitconfig ).
# Set & Print Some Basic Config Variables (Global)
$ git config --global user.email "[email protected]"
$ git config --global user.name "My Name"
$ git config --global user.email
$ git config --global user.name
To give you quick access to an extremely detailed guide of each command. Or to just give you a quick reminder of some semantics.
# Quickly check available commands
$ git help
# Check all available commands
$ git help -a
# Command specific help - user manual
# git help <command_here>
$ git help add
$ git help commit
$ git help init
# or git <command_here> --help
$ git add --help
$ git commit --help
$ git init --help
To intentionally untrack file(s) & folder(s) from git. Typically meant for private & temp files which would otherwise be shared in the repository.
$ echo "temp/" >> .gitignore
$ echo "private_key" >> .gitignore
To show differences between the index file (basically your working copy/repo) and the current HEAD commit.
# Will display the branch, untracked files, changes and other differences
$ git status
# To learn other "tid bits" about git status
$ git help status
To add files to the staging area/index. If you do not git add new files to
the staging area/index, they will not be included in commits!
# add a file in your current working directory
$ git add HelloWorld.java
# add a file in a nested dir
$ git add /path/to/file/HelloWorld.c
# Regular Expression support!
$ git add ./*.java
# You can also add everything in your working directory to the staging area.
$ git add -A
This only adds a file to the staging area/index, it doesn’t commit it to the working directory/repo.
Manage your branches. You can view, edit, create, delete branches using this command.
# list existing branches & remotes
$ git branch -a
# create a new branch
$ git branch myNewBranch
# delete a branch
$ git branch -d myBranch
# rename a branch
# git branch -m <oldname> <newname>
$ git branch -m myBranchName myNewBranchName
# edit a branch's description
$ git branch myBranchName --edit-description
Manage your tags
# List tags
$ git tag
# Create a annotated tag
# The -m specifies a tagging message, which is stored with the tag.
# If you don’t specify a message for an annotated tag,
# Git launches your editor so you can type it in.
$ git tag -a v2.0 -m 'my version 2.0'
# Show info about tag
# That shows the tagger information, the date the commit was tagged,
# and the annotation message before showing the commit information.
$ git show v2.0
# Push a single tag to remote
$ git push origin v2.0
# Push a lot of tags to remote
$ git push origin --tags
Updates all files in the working tree to match the version in the index, or specified tree.
# Checkout a repo - defaults to master branch
$ git checkout
# Checkout a specified branch
$ git checkout branchName
# Create a new branch & switch to it
# equivalent to "git branch <name>; git checkout <name>"
$ git checkout -b newBranch
Clones, or copies, an existing repository into a new directory. It also adds remote-tracking branches for each branch in the cloned repo, which allows you to push to a remote branch.
# Clone learnxinyminutes-docs
$ git clone https://github.com/adambard/learnxinyminutes-docs.git
# shallow clone - faster cloning that pulls only latest snapshot
$ git clone --depth 1 https://github.com/adambard/learnxinyminutes-docs.git
# clone only a specific branch
$ git clone -b master-cn https://github.com/adambard/learnxinyminutes-docs.git --single-branch
Stores the current contents of the index in a new “commit.” This commit contains the changes made and a message created by the user.
# commit with a message
$ git commit -m "Added multiplyNumbers() function to HelloWorld.c"
# signed commit with a message (user.signingkey must have been set
# with your GPG key e.g. git config --global user.signingkey 5173AAD5)
$ git commit -S -m "signed commit message"
# automatically stage modified or deleted files, except new files, and then commit
$ git commit -a -m "Modified foo.php and removed bar.php"
# change last commit (this deletes previous commit with a fresh commit)
$ git commit --amend -m "Correct message"
Shows differences between a file in the working directory, index and commits.
# Show difference between your working dir and the index
$ git diff
# Show differences between the index and the most recent commit.
$ git diff --cached
# Show differences between your working dir and the most recent commit
$ git diff HEAD
Allows you to quickly search a repository.
Optional Configurations:
# Thanks to Travis Jeffery for these
# Set line numbers to be shown in grep search results
$ git config --global grep.lineNumber true
# Make search results more readable, including grouping
$ git config --global alias.g "grep --break --heading --line-number"
# Search for "variableName" in all java files
$ git grep 'variableName' -- '*.java'
# Search for a line that contains "arrayListName" and, "add" or "remove"
$ git grep -e 'arrayListName' --and \( -e add -e remove \)
Google is your friend; for more examples Git Grep Ninja
Display commits to the repository.
# Show all commits
$ git log
# Show only commit message & ref
$ git log --oneline
# Show merge commits only
$ git log --merges
# Show all commits represented by an ASCII graph
$ git log --graph
“Merge” in changes from external commits into the current branch.
# Merge the specified branch into the current.
$ git merge branchName
# Always generate a merge commit when merging
$ git merge --no-ff branchName
Rename or move a file
# Renaming a file
$ git mv HelloWorld.c HelloNewWorld.c
# Moving a file
$ git mv HelloWorld.c ./new/path/HelloWorld.c
# Force rename or move
# "existingFile" already exists in the directory, will be overwritten
$ git mv -f myFile existingFile
Pulls from a repository and merges it with another branch.
# Update your local repo, by merging in new changes
# from the remote "origin" and "master" branch.
# git pull <remote> <branch>
$ git pull origin master
# By default, git pull will update your current branch
# by merging in new changes from its remote-tracking branch
$ git pull
# Merge in changes from remote branch and rebase
# branch commits onto your local repo, like: "git fetch <remote> <branch>, git
# rebase <remote>/<branch>"
$ git pull origin master --rebase
Push and merge changes from a branch to a remote & branch.
# Push and merge changes from a local repo to a
# remote named "origin" and "master" branch.
# git push <remote> <branch>
$ git push origin master
# By default, git push will push and merge changes from
# the current branch to its remote-tracking branch
$ git push
# To link up current local branch with a remote branch, add -u flag:
$ git push -u origin master
# Now, anytime you want to push from that same local branch, use shortcut:
$ git push
Stashing takes the dirty state of your working directory and saves it on a stack of unfinished changes that you can reapply at any time.
Let’s say you’ve been doing some work in your git repo, but you want to pull
from the remote. Since you have dirty (uncommitted) changes to some files, you
are not able to run git pull. Instead, you can run git stash to save your
changes onto a stack!
$ git stash
Saved working directory and index state \
"WIP on master: 049d078 added the index file"
HEAD is now at 049d078 added the index file
(To restore them type "git stash apply")
Now you can pull!
git pull
...changes apply...
Now check that everything is OK
$ git status
# On branch master
nothing to commit, working directory clean
You can see what “hunks” you’ve stashed so far using git stash list.
Since the “hunks” are stored in a Last-In-First-Out stack, our most recent
change will be at top.
$ git stash list
stash@{0}: WIP on master: 049d078 added the index file
stash@{1}: WIP on master: c264051 Revert "added file_size"
stash@{2}: WIP on master: 21d80a5 added number to log
Now let’s apply our dirty changes back by popping them off the stack.
$ git stash pop
# On branch master
# Changes not staged for commit:
# (use "git add <file>..." to update what will be committed)
#
# modified: index.html
# modified: lib/simplegit.rb
#
git stash apply does the same thing
Now you’re ready to get back to work on your stuff!
Take all changes that were committed on one branch, and replay them onto another branch. Do not rebase commits that you have pushed to a public repo.
# Rebase experimentBranch onto master
# git rebase <basebranch> <topicbranch>
$ git rebase master experimentBranch
Reset the current HEAD to the specified state. This allows you to undo merges, pulls, commits, adds, and more. It’s a great command but also dangerous if you don’t know what you are doing.
# Reset the staging area, to match the latest commit (leaves dir unchanged)
$ git reset
# Reset the staging area, to match the latest commit, and overwrite working dir
$ git reset --hard
# Moves the current branch tip to the specified commit (leaves dir unchanged)
# all changes still exist in the directory.
$ git reset 31f2bb1
# Moves the current branch tip backward to the specified commit
# and makes the working dir match (deletes uncommitted changes and all commits
# after the specified commit).
$ git reset --hard 31f2bb1
Reflog will list most of the git commands you have done for a given time period, default 90 days.
This give you the chance to reverse any git commands that have gone wrong (for instance, if a rebase has broken your application).
You can do this:
git reflog to list all of the git commands for the rebase38b323f HEAD@{0}: rebase -i (finish): returning to refs/heads/feature/add_git_reflog
38b323f HEAD@{1}: rebase -i (pick): Clarify inc/dec operators
4fff859 HEAD@{2}: rebase -i (pick): Update java.html.markdown
34ed963 HEAD@{3}: rebase -i (pick): [yaml/en] Add more resources (#1666)
ed8ddf2 HEAD@{4}: rebase -i (pick): pythonstatcomp spanish translation (#1748)
2e6c386 HEAD@{5}: rebase -i (start): checkout 02fb96d
2e6c386, or HEAD@{5}Revert can be used to undo a commit. It should not be confused with reset which restores the state of a project to a previous point. Revert will add a new commit which is the inverse of the specified commit, thus reverting it.
# Revert a specified commit
$ git revert <commit>
The opposite of git add, git rm removes files from the current working tree.
# remove HelloWorld.c
$ git rm HelloWorld.c
# Remove a file from a nested dir
$ git rm /pather/to/the/file/HelloWorld.c
Examine specific parts of the code’s history and find out who was the last author to modify that line.
# find the authors on the latest modified lines
$ git blame google_python_style.vim
b88c6a1b (Google Python team 2019-12-30 13:45:23 -0800 12) " See the License for the specific language governing permissions and
b88c6a1b (Google Python team 2019-12-30 13:45:23 -0800 13) " limitations under the License.
b88c6a1b (Google Python team 2019-12-30 13:45:23 -0800 14)
222e6da8 ([email protected] 2010-11-29 20:32:06 +0000 15) " Indent Python in the Google way.
222e6da8 ([email protected] 2010-11-29 20:32:06 +0000 16)
222e6da8 ([email protected] 2010-11-29 20:32:06 +0000 17) setlocal indentexpr=GetGooglePythonIndent(v:lnum)
Learn Git Branching - the most visual and interactive way to learn Git on the web
Git Immersion - A Guided tour that walks through the fundamentals of git
The New Boston tutorial to Git covering basic commands and workflow
Got a suggestion? A correction, perhaps? Open an Issue on the GitHub Repo, or make a pull request yourself!
Originally contributed by Jake Prather, and updated by 36 contributors.