ubuntu@ubuntu:~$ sudo umount /dev/sdc
umount: /dev/sdc: not mounted
ubuntu@ubuntu:~$ sudo umount /dev/sdc
umount: /dev/sdc: not found
ubuntu@ubuntu:~$ sudo lsblk -o NAME,FSTYPE,SIZE,MOUNTPOINT,LABEL
NAME   FSTYPE     SIZE MOUNTPOINT LABEL
sda             465.8G            
├─sda1 ntfs       100M            System Reserved
├─sda2 ntfs     194.6G            
├─sda3              1K            
├─sda5 ext4     255.1G            
└─sda6 swap      15.9G [SWAP]     
sdb                 2G            
└─sdb1 vfat         2G /cdrom     
loop0  squashfs 962.1M /rofs      
ubuntu@ubuntu:~$ sudo dd if=/dev/sda | pv | sudo dd of=/dev/sdc bs=512 conv=noerror,sync
dd: error writing ‘/dev/sdc’: No space left on device   <=>                    ]
16310897+0 records in
16310896+0 records out
8351178752 bytes (8.4 GB) copied, 70.1363 s, 119 MB/s
7.78GB 0:01:10 [ 114MB/s] [                            <=>                     ]
ubuntu@ubuntu:~$