ubuntu@ubuntu:~$ sudo fdisk -l

Disk /dev/sda: 1000.2 GB, 1000204886016 bytes
255 heads, 63 sectors/track, 121601 cylinders, total 1953525168 sectors
Units = sectors of 1 * 512 = 512 bytes
Sector size (logical/physical): 512 bytes / 4096 bytes
I/O size (minimum/optimal): 4096 bytes / 4096 bytes
Disk identifier: 0x6fa8e725

   Device Boot      Start         End      Blocks   Id  System
/dev/sda1   *        2048      718847      358400    7  HPFS/NTFS/exFAT
/dev/sda2          718848  1654547296   826914224+   7  HPFS/NTFS/exFAT
/dev/sda3      1654548480  1748721663    47086592    7  HPFS/NTFS/exFAT
/dev/sda4      1748723710  1953523711   102400001    5  Extended
Partition 4 does not start on physical sector boundary.
/dev/sda5      1748723712  1945352191    98314240   83  Linux
/dev/sda6      1945354240  1953523711     4084736   82  Linux swap / Solaris

Disk /dev/sdb: 2004 MB, 2004877312 bytes
62 heads, 62 sectors/track, 1018 cylinders, total 3915776 sectors
Units = sectors of 1 * 512 = 512 bytes
Sector size (logical/physical): 512 bytes / 512 bytes
I/O size (minimum/optimal): 512 bytes / 512 bytes
Disk identifier: 0x20ac7dda

This doesn't look like a partition table
Probably you selected the wrong device.

   Device Boot      Start         End      Blocks   Id  System
/dev/sdb1   ?  3224498923  3657370039   216435558+   7  HPFS/NTFS/exFAT
/dev/sdb2   ?  3272020941  5225480974   976730017   16  Hidden FAT16
/dev/sdb3   ?           0           0           0   6f  Unknown
/dev/sdb4        50200576   974536369   462167897    0  Empty

Partition table entries are not in disk order