#!/usr/bin/env sh
# $0 is a script name, 
# $1, $2, $3 etc are passed arguments
# $1 is our command
CMD=$1
case "$CMD" in  
  "dev" )
    ;;
  "start" )
    # we can modify files here, using ENV variables passed in 
    # "docker create" command. It can't be done during build process.
    exec ./run.sh
    ;;
   * )
    # Run custom command. Thanks to this line we can still use 
    # "docker run our_image /bin/bash" and it will work
    exec $CMD ${@:2}
    ;;
esac