What I typically do is mount the USB drive in an isolated virtual machine. But this requires you have a hypervisor installed and a guest operation system configured, etc. This works because I can snapshot the VM state as well as isolate at the network level. But it's too complicated to explain here.

Probably the easiest way to do this is to mount the drive as read-only. You can do this by using diskutil from Terminal.


Open /Applications/Utilities/Terminal.
Insert the drive into a USB port.
Run diskutil list from Terminal and note the disk number for your USB drive. Here's what my output looked like



  $ diskutil list
  /dev/disk0
    #:                       TYPE NAME                    SIZE       IDENTIFIER
    0:      GUID_partition_scheme                        *251.0 GB   disk0
    1:                        EFI EFI                     209.7 MB   disk0s1
    2:          Apple_CoreStorage                         250.1 GB   disk0s2
    3:                 Apple_Boot Recovery HD             650.0 MB   disk0s3
  /dev/disk1
    #:                       TYPE NAME                    SIZE       IDENTIFIER
    0:                  Apple_HFS Macintosh HD           *249.8 GB   disk1
                                  Logical Volume on disk0s2
                                  5F6A08FD-AD5D-4C63-9DF2-8C1DE409F264
                                  Unencrypted
  /dev/disk2
    #:                       TYPE NAME                    SIZE       IDENTIFIER
    0:      GUID_partition_scheme                        *32.7 GB    disk2
    1:                        EFI EFI                     209.7 MB   disk2s1
    2:                  Apple_HFS TomThumb                32.4 GB    disk2s2


So my USB drive is disk2.


Eject the disk by running diskutil unmountDisk /dev/diskX (which would be "disk2" for me)
Remount disk in read only mode by running diskutil mountDisk readOnly /dev/diskX
Use Finder or Terminal to examine the disk.


Note that if you eject the drive, you'd need to run this sequence again to have it mount as read only. There are other apps that automate mounting disks as read only but the command line is the only real UI for any OS! ;-) #opinion

How can I check USB drive contents safely?
I'm a bit of a bridge noob, but I'm kind of puzzled about this. Say I have a hand that is ridiculously strong in one suit, say at least 10 cards with all 4 honors (I'll use spades for the example suit). how should I bid? This is so many cards that almost nobody will be leading spades but me, so if another suit is trump, I'm flush out of luck.

Obviously I would want to end up playing a spade contract with a good potential for a slam, but if I open too high, say 5 spades, won't my opponents catch on pretty quickly and bid in their own suits or No-trump, just so my spades will be next to useless? They will likely have favorable distributions for their own suits since nearly all the spades are gone, which only worsens the fact. Then again, if I bid to low, my partner may not rebid, and while taking 12 tricks at a contract of 3S is obviously good, knowing you will have that many overtricks from the start seems kind of a waste.

Even if I held 12 or 13 spades, if I bid 7S, won't my opponents just bid 7NT and I'll never get to lead? How should hands with this heavy a distribution be bid to make the most of them?

(I've already said I'm not a very experienced bridge player, so if I'm making any glaring oversights don't hesitate in the slightest to bring them up.)



NOTE: I know these hands are extremely rare, but in all reality, every single possible hand is rare enough that studying bridge hands is actually quite useless because you'll never see the same hand again in your life...but we do it anyway because that's how we learn. Couldn't you tell anyone asking about a specific hand not to worry about it because it'll never show up again? :D
