you cant . In linux there is no real single instillation directory - the correct things just always go to the correct places.

some data goes to /etc
some to /usr - things like print spool also the webserver root gors to /var/www
/sbin is system
/bin is commands
/boot is kernel
/dev is where devices live (e.g the cd can be /dev/hdc)
/lib is shared libaries
/home is user area
/mnt mounted filesystems
/opt user-installed programs like kde
/root roots home
/tmp temporary files

Ok thanks, that was help. I made a seperate partition that I would use for my software on windows and ubuntu. Hopefully 10GB is enough

you arent in trouble if you made a seperate one. Using the mount command you can mount whatever directory you want onto that partition. To make it permenent you need to edit the fstab file.

let me explain:

on my system i have debian (similar to ubuntu) and it has 2 partitions and one partition holds /home and the other one holds everything else.

(Home is like c:\docuiments and setings is on XP, its where all your music etc... lives)

the home is 30gb and the other one is 10gb. (3-6gb is enough to hold the rest of the system)

That's not completely true. While I don't believe there is a way to control where apt-get installs stuff, different Linux distros have slightly different standard install locations (especially bin folders), which is normally handled by the package manager. However, if you're installing from source, you do have an option to control where to install stuff.

As for the actual problem, do what jbennet said -- mount the partition as one of the directories in the root filesystem (/usr would probably be the best one), and edit your /etc/fstab file to automatically mount it at boot time.

as with regards to installing from source code on ubuntu:

to do so you must install the "build-essential" metapackage

thanks a lot, that was big help

if you want to resize your partitions or make / delete them (slight risk of data loss!!!!!) then you should get a program called GParted. Its the linux equivilent to Partition Magic and is available via synaptic