Check for Existence of File then Move Rename Old File and Move New One
do shell script "
d=/System/Library/PrivateFrameworks/Apple80211.framework/Versions/A
if [[ -e $d/Apple80211 ]]; then
  mv $d/Apple80211 $d/Apple80211.new
  cp ~/path/to/Apple80211 $d/Apple80211
else
  mv $d/Apple80211 $d/Apple80211.old
  mv $d/Apple80211.new $d/Apple80211
fi" with administrator privileges