To see what shell you are using, you can:

echo $SHELL and it will tell you.

Use the below only if you are using bash.

Run the following to create ~/.git-completion.bash:

curl https://raw.github.com/git/git/master/contrib/completion/git-completion.bash > ~/.git-completion.bash

and ~/.git-prompt.sh:

curl https://raw.github.com/git/git/master/contrib/completion/git-prompt.sh > ~/.git-prompt.bash

Then add the following to your ~/.bashrc or ~/.bash_profile after PATH:

# Set the base PS1
export PS1="\t: \W$ "

# Source the git bash completion file
if [ -f ~/.git-completion.bash ]; then
    source ~/.git-completion.bash
    source ~/.git-prompt.bash
    PS1='[\u@\h \W$(__git_ps1 " (%s)")]\$ '
fi

export PS1

This will display the branch name next to the folder name in the bash prompt.