Resize VirtualBox Hard Drive

Use the following command to resize a VirtualBox Hard Drive in Linux. It may or may not work in Windows as well.

VBoxManage modifyhd YOUR_HARD_DISK.vdi --resize SIZE_IN_MB

40960 MB = 40 GB

Source: http://www.webupd8.org/2011/02/how-to-easily-resize-virtualbox-40-hard.html

Note: Running this command on a RHEL5.8 x86_64 VM caused errors when logging in as users other than root. I believe the partitions inside the VM will need to be resized as well, after running this command.