4 Basic Operations FAQ

3.7 Source code--the ultimate resource

The ultimate reference under Linux is the source code. If you installed it (comes with standard distributions; we really recommend its installation if you have enough hard drive space), it is in /usr/src/linux(the kernel source) and /usr/src/RPM/sources(the source code for the balance of the rpm packages). How can the source code be of use to a newbie? Well, it contains all the comments and documentation down to the smallest detail. For example, later in this guide, we show how to read/set up some of the kernel runtime parameters via the /proc filesystem. You can read the complete documentation for all the available parameters using:

less /usr/src/linux/Documentation/proc.txt

To install kernel sources, I would select the appropriate rpm package during my main installation. To install sources for other packages that came with my distribution, I would put the "Source CD" into the cd drive and do something like (as root, with RedHat CD):

[install the source code for the gnumeric spreadsheet from the cd to the harddrive]

su

cd /mnt/cdrom/SRPMS/

rpm -ivh gnume<Tab>

[unzip the sourcecode which I just installed]

cd /usr/src/RPM/SOUR<Tab>

tar -xvzf gnumer<Tab>

[read the code for statistical functions in gnumeric]

cd gnumeric/src/functions

less fn-stat.c

This is truly the ultimate reference on how a particular spreadsheet function works, no kidding.