$ cat /proc/partitions
major minor #blocks name
8 0 488386584 sda
8 1 73400953 sda1
8 2 1 sda2
8 5 102406311 sda5
8 6 102406311 sda6
8 7 1998848 sda7
8 8 208171008 sda8
11 0 1048575 sr0