run script on cd'ing into and out of a directory

onCD bash

# onCD
# -----
# Place the code below in your .bashrc file.
# then place a script in any directory, named 'oncd.sh'
# the script will receive an argument of 'enter' or 'leave'
# when cd'ing into or out of the directory.

#(doesn't work with "shopt -s autocd", use COMMAND_PROMPT for that)
cd () {
  oldpath=$PWD
  builtin cd "$@" && oncd $oldpath
}
# these need more work
# pushd () { builtin pushd "$@" && oncd "enter" }
# popd () { builtin popd "$@" && oncd "enter" }
oncd () {
  #echo "oldpath: $1"
  [[ -f "$1/oncd.sh" ]] && sh $1/oncd.sh "leave"
  [[ -f "oncd.sh" ]] && sh oncd.sh "enter"
}