gparted

GParted is an industrial-strength package for creating, destroying, resizing, checking and copying partitions, and the file systems on them. This is useful for creating space for new operating systems, reorganizing disk usage, copying data residing on hard disks and mirroring one partition with another (disk imaging).

A hard disk is usually subdivided into one or more partitions. These partitions are normally not re-sizable (making one larger and the adjacent one smaller) The purpose of GParted is to allow the individual to take a hard disk and change the partition organization therein, while preserving the partition contents.