shaikmustaq63 / how-to-use-github

This is the supplementary material for "How to Use GitHub" By Siraj Raval on Youtube

Overview

These are a list of useful commands from this video on Youtube by Siraj Raval.

Useful Git Commands

About it

Have you recently started using Git? This should give you the base commands you need to perform the most common actions in Git. If you find a command that is not here, or could be explained better, please don't hesitate in * Contributing. Cheers!

Table of contents

• Install git
• Setting up git
• Applying colour to git
• Initializing a repository in an existing directory
• Checking the status of your files
• Staging files
• Stashing files
• Committing files
• Branching and merging
• Resetting
• Git remote
• Git grep
• Git blame
• Git log
• Checking what you are committing
• Useful Commands
• Useful Alias
• Contributing

Git

Git is a distributed version control system, very easy to learn and supper fast!

Install Git

There are a few different ways to install git (from source or for Linux) but the purpose of this page is to focus on git commands, so I am going to assume you are installing git on a Mac.

To view other ways of installing it visit the Git official site

Click here to download and install Git

Setting up git

$ git config --global user.name "User Name"

$ git config --global user.email "email"

Applying colour to git

$ git config --global color.ui true

Initializing a repository in an existing directory

If you’re starting to track an existing project in Git, you need to go to the project’s directory and type:

$ git init

This creates a new subdirectory named .git that contains all of your necessary repository files — a Git repository skeleton. At this point, nothing in your project is tracked yet.

To start version-controlling existing files you should start by tracking those files and do an initial commit. To accomplish that you should start with a few $ git add that specifies the files you want to track followed by a commit.

$ git add <file>
$ git add README
$ git commit -m 'Initial project version'

Checking the status of your files

The main tool you use to determine which files are in which state is the $ git status command. If you run this command directly after a clone, you should see something like this:

$ git status
# On branch master
nothing to commit (working directory clean)

If you add a new file to your project, and the file didn't exist before, when you run a $ git status you should see your untracked file like this:

$ git status
# On branch master
# Untracked files:
#   (use "git add <file>..." to include in what will be committed)
#
#   README
nothing added to commit but untracked files present (use "git add" to track)

Staging files

After initializing a git repository in the chosen directory, all files will now be tracked. Any changes made to any file will be shown after a $ git status as changes not staged for commit.

To stage changes for commit you need to add the file(s) - or in other words, stage file(s).

# Adding a file
$ git add filename

# Adding all files
$ git add -A

# Adding all files changes in a directory
$ git add .

# Choosing what changes to add (this will got through all your changes and you can 'Y' or 'N' the changes)
$ git add -p

Stashing files

Git stash is a very useful command, where git will 'hide' the changes on a dirty directory - but no worries you can re-apply them later. The command will save your local changes away and revert the working directory to match the HEAD commit.

# Stash local changes
$ git stash

# Stash local changes with a custom message
$ git stash save "this is your custom message"

# Re-apply the changes you saved in your latest stash
$ git stash apply

# Re-apply the changes you saved in a given stash number
$ git stash apply stash@{stash_number}

# Drops any stash by its number
$ git stash drop stash@{0}

# Apply the stash and then immediately drop it from your stack
$ git stash pop

# 'Release' a particular stash from your list of stashes
$ git stash pop stash@{stash_number}

# List all stashes
$ git stash list

# Show the latest stash changes
$ git stash show

# See diff details of a given stash number
$ git diff stash@{0}

Committing files

After adding/staging a file, the next step is to commit staged file(s)

# Commit staged file(s)
$ git commit -m 'commit message'

# Add file and commit
$ git commit filename -m 'commit message'

# Add file and commit staged file
$ git commit -am 'insert commit message'

# Amending a commit
$ git commit --amend 'new commit message' or no message to maintain previous message

# Squashing commits together
$ git rebase -i
This will give you an interface on your core editor:
# Commands:
#  p, pick = use commit
#  r, reword = use commit, but edit the 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 this commit's log message
#  x, exec = run command (the rest of the line) using shell

# Squashing commits together using reset --soft
$ git reset --soft HEAD~number_of_commits
$ git commit
** WARNING: this will require force pushing commits, which is OK if this is on a branch before you push to master or create a Pull Request.

Branching and merging

# Creating a local branch
$ git checkout -b branchname

# Switching between 2 branches (in fact, this would work on terminal as well to switch between 2 directories - $ cd -)
$ git checkout -

# Pushing local branch to remote
$ git push -u origin branchname

# Deleting a local branch - this won't let you delete a branch that hasn't been merged yet
$ git branch -d branchname

# Deleting a local branch - this WILL delete a branch even if it hasn't been merged yet!
$ git branch -D branchname

# Remove any remote refs you have locally that have been removed from your remote (you can substitute <origin> to any remote branch)
$ git remote prune origin

# Viewing all branches, including local and remote branches
$ git branch -a

# Viewing all branches that have been merged into your current branch, including local and remote
$ git branch -a --merged

# Viewing all branches that haven't been merged into your current branch, including local and remote
$ git branch -a --no-merged

# Viewing local branches
$ git branch

# Viewing remote branches
$ git branch -r

# Rebase master branch into local branch
$ git rebase origin/master

# Pushing local branch after rebasing master into local branch
$ git push origin +branchname

Fetching and checking out remote branches

# This will fetch all the remote branches for you.
$ git fetch origin

# With the remote branches in hand, you now need to check out the branch you are interested in, giving you a local working copy:
$ git checkout -b test origin/test

# Deleting a remote branch
$ git branch -rd origin/branchname
$ git push origin --delete branchname  or  $ git push origin:branchname

Merging branch to trunk/master

# First checkout trunk/master
$ git checkout trunk/master

# Now merge branch to trunk/master
$ git merge branchname

# To cancel a merge
$ git merge --abort

Updating a local repository with changes from a Github repository

$ git pull origin master

Tracking existing branch

$ git branch --set-upstream-to=origin/foo foo

Resetting

# Mixes your head with a give sha
# This lets you do things like split a commit
$ git reset --mixed [sha]

# Upstream master
$ git reset HEAD origin/master -- filename

# The version from the most recent commit
$ git reset HEAD -- filename

# The version before the most recent commit
$ git reset HEAD^ -- filename

# Move head to specific commit
$ git reset --hard sha

# Reset the staging area and the working directory to match the most recent commit. In addition to unstaging changes, the --hard flag tells Git to overwrite all changes in the working directory, too.
$ git reset --hard

Git remote

# Show where 'origin' is pointing to and also tracked branches
$ git remote show origin

# Show where 'origin' is pointing to
$ git remote -v

# Change the 'origin' remote's URL
$ git remote set-url origin https://github.com/user/repo.git

# Add a new 'origin'
# Usually use to 'rebase' from forks
$ git remote add [NAME] https://github.com/user/fork-repo.git

Git grep

# 'Searches' for parts of strings in a directory
$ git grep 'something'

# 'Searches' for parts of strings in a directory and the -n prints out the line numbers where git has found matches
$ git grep -n 'something'

# 'Searches' for parts of string in a context (some lines before and some after the grepped term)
$ git grep -C<number of lines> 'something'

# 'Searches' for parts of string and also shows lines BEFORE the grepped term
$ git grep -B<number of lines> 'something'

# 'Searches' for parts of string and also shows lines AFTER the grepped term
$ git grep -A<number of lines> 'something'

Git blame

# Show alteration history of a file with the name of the author
$ git blame [filename]

# Show alteration history of a file with the name of the author && SHA
$ git blame [filename] -l

Git log

# Show a list of all commits in a repository. This command shows everything about a commit, such as commit ID, author, date and commit message.
$ git log

# List of commits showing commit messages and changes
$ git log -p

# List of commits with the particular expression you are looking for
$ git log -S 'something'

# List of commits by author
$ git log --author 'Author Name'

# Show a list of commits in a repository in a more summarised way. This shows a shorter version of the commit ID and the commit message.
$ git log --oneline

# Show a list of commits in a repository since yesterday
$ git log --since=yesterday

# Shows log by author and searching for specific term inside the commit message
$ git log --grep "term" --author "name"

Checking what you are committing

# See all (non-staged) changes done to a local repo
$ git diff

# See all (staged) changes done to a local repo
$ git diff --cached

# Check what the changes between the files you've committed and the live repo
$ git diff --stat origin/master

Useful commands

# Check if a sha is in production
$ git tag --contains [sha]

# Number of commits by author
$ git shortlog -s --author 'Author Name'

# List of authors and commits to a repository sorted alphabetically
$ git shortlog -s -n

# List of commit comments by author
$ git shortlog -n --author 'Author Name'
# This also shows the total number of commits by the author

# Number of commits by contributors
$ git shortlog -s -n

# Undo local changes to a File
$ git checkout -- filename

# Shows more detailed info about a commit
$ git cat-file sha -p

# Show number of lines added and removed from a repository by an author since some time in the past.
$ git log --author="Author name" --pretty=tformat: --numstat --since=month | awk '{ add += $1; subs += $2; loc += $1 - $2 } END { printf "added lines: %s, removed lines: %s, total lines: %s\n", add, subs, loc }'

Useful alias

To add an alias simply open your .gitconfig file on your home directory and include the alias code

# Shows the log in a more consisted way with the graph for branching and merging
lg = log --color --graph --pretty=format:'%Cred%h%Creset -%C(yellow)%d%Creset %s %Cgreen(%cr) %C(bold blue)<%an>%Creset' --abbrev-commit

Contributing

1. Fork it!
2. Create your feature branch: git checkout -b my-new-feature
3. Commit your changes: git commit -m 'Add some feature'
4. Push to the branch: git push -u origin my-new-feature
5. Submit a pull request - cheers!