Redhat:fdisk
Fdisk
fdisk is a utiltiy available on Linux and Mac. Its also available on Windows through DOS, however it will only work for windows partitions.
fdisk Help
To start fdisk run the command passing it a disk as a parameter. When its started you may see a warning about being compatible with DOS. The changes do not need to be made, but if you do they will have to be made every time you start fdisk. Making the changes will however remove the warnings and make the results more precise.
fdisk /dev/sdbfdisk and a new drive
When adding a new drive to linux, its likely to have no partitions. When you start fdisk on the new drive, it will give you a message stating that no partitions are defined.
It will also say that it will give the drive a new 'DOS disklabel' Yes despite the DOS warning at the start, fdisk still uses DOS.
A drive can only contain four primary partitions. If more than four partitions are needed, the fourth partition needs to be an extended partition. An extended partition can contain several other paritions.