This posts will help you understand what a git alias is and some of the basic ones I use.

What's a git alias?

In the computer science domain, alias means an alternative name or label that refers to a file, command, address, or other items, and can be used to locate or access it.

So, basically with git alias, the idea is that you create shorter alias for the most commonly used commands, to reduce the amount of typing that you do.

How to use them?

To use them, add the commands to your .bash_profile, .bashrc or .gitconfig file. Once you add them run the source .bash_profile command.

You can add them by using command line also, but would not recommend it as it would be very verbose and difficult to manage over time.

$ git config --global alias.co checkout

Common commands

alias gc='git checkout'
alias gcm='git commit -m'
alias gs='git status'
alias ga='git add --all'
alias gp='git pull --rebase'
alias gb='git branch -vv'
alias gr='git remote -v'
alias grt='git reset --hard'
alias gpub='git push origin master'
alias grp='git rebase master'
alias gd='git branch -D'
alias gm='git merge'
alias gmx='git merge -X theirs'
alias gk='gitk &'
alias gda='git branch | grep -v "develop" | grep -v "release" | xargs git branch -D'
alias gf='git fetch'
alias gl='git log -3'

# cleans all branches locally that have already been merged.
alias gcmb="git branch --merged | grep -Ev '(^\*|develop)' | xargs git branch -d"

Another good resource here to enable a quicker workflow I also use the git-extras. It allows an abstraction on more complicated git workflows.