| Command | Notes |
|---|---|
| md5sum myfile.txt | Hash file |
| md5deep mydir | Hash all files in dir |
| sha512sum | Hash file |
| cmp file1 file2 | Run a diff on the two files |
| mount /dev/sda1 /mnt | Mount partition 1 to /mnt. Run with sudo |
| umount /dev/sda1 | Unmount /dev/sda1 |
| umount /mnt | As above |
| losetup /dev/loop0 /images/image.dd | Create a loop device so that we can mount a disk image |
| losetup /dev/loop0 /images/image.dd -o 1048576 | As above but mounting a partition. The offset is blocks * block size (eg 2048 * 512) |
| mount /dev/loop0 /mnt -o ro | Mount the above loop device in read only format (must use -o ro) |
| umount /dev/loop0 | Unmount the loop device |
| losetup -d /dev/loop0 | Delete the loop device |
| dd if=/dev/zero of=/root/changes bs=512 seek=4095 count=1 | Create a sparse file ready for snapshots. This eg creates a 2mb file that is only 4kb and will hold our changes. |
| losetup /dev/loop1 /root/changes | Create a loop device from the sparse file |
| blockdev --getsz /dev/loop0 | Get the block size of the image |
| dmsetup create sandbox --table "0 THESIZE snapshot /dev/loop0 /dev/loop1 N 1" | Create the snapshot. THESIZE is the size reported back from blockdev |
| mount /dev/mapper/sandbox /mnt | Mount the snapshot. May need to "sync" after copying files to it by just running $ sync |
| dmsetup remove sandbox | Remove the sandbox |