To set xterm-256color and nice prompt for git on Ubuntu

.bashrc

# Useful but slow against very large repositories.
GIT_PS1_SHOWDIRTYSTATE=true

# Use __git_ps1 function from git contributed package to do the work.
if [ "$color_prompt" = yes ]; then
    PS1='${debian_chroot:+($debian_chroot)}\[\033[01;32m\]\u@\h\[\033[00m\]:\[\033[01;34m\]\w\[\033[1;33m\]$(__git_ps1 " (%s)")\[\033[00m\]\$ '
else
    PS1='${debian_chroot:+($debian_chroot)}\u@\h:\w$(__git_ps1 " (%s")\$ '
fi

# Set 256 colour terminal when the definition is present.
if [ -e /usr/share/terminfo/x/xterm-256color ]; then
    TERM='xterm-256color'
else
    TERM='xterm-color'
fi

# Set a fancy prompt (non-color, unless we know we "want" colour).
case "$TERM" in
    xterm-color) color_prompt=yes;;
    xterm-256color) color_prompt=yes;;
esac

# Typing "git" all the time is simply too much work.
alias g='git'