the triple decker super checker

triple_deck_check

# fast & efficient triple check:
# existence, directory, writable || or error and exit
[[ -e  $DIR && -d $DIR && -w $DIR ]]  || { echo >&2 "Unable to access $DIR - check directory path / permissions?" ; exit 1 ; }

# exists , file, readable
[[ -s  $FILE && -d $FILE && -r $FILE ]]  || { echo >&2 "Unable to access $FILE - check file path / permissions?" ; exit 1 ; }

# exists , file, writable
[[ -s  $FILE && -d $FILE && -w $FILE ]]  || { echo >&2 "Unable to access $FILE - check file path / permissions?" ; exit 1 ; }