执行 mountpoint -q /test/mount
echo $? 如果是0表示已经mount
mountpoint -q /test/mount || mount -o bind /some/directory/here /test/mount
执行 mountpoint -q /test/mount
echo $? 如果是0表示已经mount
mountpoint -q /test/mount || mount -o bind /some/directory/here /test/mount