The safest way is to do it in small steps, and checking if every step works:
- Create a partition in the empty space.
- Create a
ext4file system in the new partition.
You can use Gparted for these steps. Let's say the new partition will be called
Create a mount point in your home directory:
Mount the new partition on the mount point:
sudo mount /dev/sdb5 ~/mydata
You have now enlarged your home directory by 66 Gb. Use it to store your files. If all of this works, you can consider adding a line to
/etc/fstab so the partition will be automatically mounted after the next reboot.
The safest way is:
- backup everything to external drive with say Clonezilla
- try to enlarge current partition with GParted using GParted try-run (you can use GParted live cd for that puprose)
- actually enlarge the partition with GParted - you have "Resize" option in the menu or simply klick and drag left side of the box to the left
- reboot and make fsck that, I think, is included on GParted live media (if not Knoppix includes it for sure)
Reboot and voilà, it works.
Note that having the whole Linux on one partition is ok for home system, but for more serious uses consider lvm and several partitions for different parts of the system like home, var, boot, swap, etc.