Configure things:
git config --global user.name "Your Name"
git config --global user.email "you@example.com"
git config --global alias.co checkout
git config --global apply.whitespace nowarn
Setup an SSH key
ssh-keygen
Hit return a couple of times -- leave password blank if you want.
cat ~/.ssh/id_rsa.pub | pbcopy
Paste that code into your settings page on your repository host(s).
Set up Global Git Config on your GitHub account page (the same place you pasted your SSH key). You'll type in some stuff that looks like this:
git config --global github.user [your_username]
git config --global github.token [your_token]
Get happy Git colors. Paste the following into your ~/.gitconfig file:
[color]
branch = auto
diff = auto
status = auto
[color "branch"]
current = yellow reverse
local = yellow
remote = green
[color "diff"]
meta = yellow bold
frag = magenta bold
old = red bold
new = green bold
[color "status"]
added = yellow
changed = green
untracked = cyan
Create a ~/.gitexcludes file and paste in this:
.DS_Store
There, now you don't have to ignore that every time.
Add the following to your ~/.bash_profile or ~/.bashrc:
source /usr/local/git/contrib/completion/git-completion.bash
GIT_PS1_SHOWDIRTYSTATE=true
export PS1='[\u@mbp \w$(__git_ps1)]\$ '
That will add tab auto-completion for Git branches, display the current branch on your prompt, and show a '*' after the branch name if there are unstaged changes in the repository, and a '+' if there are staged (but uncommitted) changes. It will look something like this:
[user@computer ~/Sites/example.com (master*)]$
If you want to have a different email address for a particular project (a personal project on your work computer, perhaps?), just run this command inside that project's folder:
git config user.email "you@example.com"
It's the same command as before, this time just omitting the --global.