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When I plug a device such as an SD card into my Ubuntu computer, I understand that Linux automatically mounts the device. So when I run fdisk -l , the device will appear as for example /dev/sdb . Does this mean that the device is now mounted or not?

To me, mounting means making the device available to the file system. The device seems available to the file system in this case.

Now if I run umount /dev/sdb it states that the device is not mounted. Confusing

marked as duplicate by don_crissti, Rui F Ribeiro linux Jan 6 at 12:52

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