bash/zsh prompt support to check if Vagrantfile exists.

.bashrc

# Add or custome for your .bashrc

source ~/.vagrant-prompt.sh
export PS1='\u@\h \W\[\033[33m\]$(__vagrant_pt)\[\033[00m\] $ '

.vagrant-prompt.sh

#!/bin/sh
# bash/szh vagrant prompt support

__vagrant_pt(){
  dirname=$(pwd)

  # prevent to trap while, when you are on not-existing dir
  if [[ ! -d $dirname ]]; then
      return
  fi

  if [[ -e "$dirname/Vagrantfile" ]]; then
      echo "[vm]"
  else

      while [ "$dirname" != "/" ]
      do
          dirname=$(cd $dirname/..;pwd)
          if [[ -e $dirname/Vagrantfile ]]; then
            echo "[>vm]"
            break
          fi
      done
  fi
}

.zshrc

# Add or custome for your .zshrc

setopt PROMPT_SUBST

source ~/.vagrant-prompt.sh
export PS1='%n@%m %c%F{yellow}$(__vagrant_pt)%f \$ '