DEST_DIR=/usr/share
GREP=grep

file_exists_exact1()
{
        [ -n "$1" ] || err 3 "USAGE: file_exists_exact path"
        _path="${1#.}"
        [ -h "${DEST_DIR}${_path}" ] || \
                [ -e "${DEST_DIR}${_path}" ] || return 1
        while [ "${_path}" != "/" ] ; do
                _dirname="$(dirname "${_path}" 2>/dev/null)"
                _basename="$(basename "${_path}" 2>/dev/null)"

                ls -fa "${DEST_DIR}${_dirname}" 2> /dev/null \
                        | ${GREP} -F -x "${_basename}" >/dev/null \
                        || return 1

                _path="${_dirname}"
        done
        return 0
}

file_exists_exact2()
{
        [ -n "$1" ] || err 3 "USAGE: file_exists_exact path"
        _path="${1#.}"
        [ -h "${DEST_DIR}${_path}" ] || \
                [ -e "${DEST_DIR}${_path}" ] || return 1
        while [ "${_path}" != "/" ] ; do
		_dirname=${_path%/*}
		_basename=${_path##*/}
		test -n "$_dirname" || _dirname=/

		(
			cd "${DEST_DIR}${_dirname}"
			for _entry in .* *; do
				case ${_entry} in
				"${_basename}") return 0;;
				esac
			done
			return 1
		) || return 1

                _path="${_dirname}"
        done
        return 0
}

DEST_DIR="$2"
if file_exists_exact$1 "$3" ; then
	echo "$3" exists in "$2"
fi

.