Display the current gemset in your prompt.

ps1.sh

# The important bit in this short example
# is the call to the _gemset function.
export PS1='$(_gemset)\w \$ '

# This function checks if the GS_NAME variable
# has a value and returns either an empty string
# or the name of the current gemset.
_gemset() {
  if [[ -z $GS_NAME ]]; then
    echo ""
  else
    echo "$GS_NAME "
  fi  
}