Partitioning
 

I have a dual boot Toshiba laptop and I wish to modify my partition(s)
shown below:
Filesystem 1K-blocks Used Available Use% Mounted on
/dev/sda7 20642428 16503680 3090172 85% /
devtmpfs 1924192 232 1923960 1% /dev
tmpfs 1925628 7980 1917648 1% /dev/shm
/dev/sda8 80486216 5306276 71091468 7% /home
/dev/sda2 105769140 71410356 34358784 68% /windows/C
/dev/sda4 9767932 9142600 625332 94% /windows/D
/dev/sda5 90646728 6039920 84606808 7% /windows/E

I wish to increase /dev/sda7 to 40Gig while decreasing /dev/sda8 to 60 Gig without messing the system up. Can anyone please tell me how to please. Thanks

Have a look at GParted. This can do what you want.

Yes Snoqma,
GParted can do resize, copy, and move partitions without data loss.

Partitioning
 

Do you guys have a tutorial I can follow ? Thanks

you could start by here .

especially this link

Partition
 

GParted can create a partion but I don't think it can merge partitions.

you won't be merging them .

you will use the resize tool in this case : lower the size of the partition you want ,move the partitions around so that the free space comes after the partition you want to make bigger , and then use the resize tool again and extend it .