When the user has changed into a git directory, rebase with upstream if there are no uncommitted files.

quesadilla.bash

function cd {
    # Run the system CD command on the parameters that were passed in
    builtin cd "$@"
    # Check if the directory we are in now is a git directory
    if [ -d ".git" ]; then
        # If so, check to see that there are no uncommitted files
        if [ $(git status --porcelain 2>/dev/null| egrep "^(M| M)" | wc -l) ]; then
            # Rebase our current branch with upstream/master
            git fetch upstream && git rebase upstream/master
        fi
    fi
}