The tool for linking is 'ld'. Try 'man ld' for the arguements the ld linker takes.
when you call gcc to compile, it automatically calls the linker for you with the suitable arguments.
For example if you have object files, you made by eg. 'gcc -c'. And you'd like to link them, you can call 'gcc file1.o file2.o ...'. or you can call 'ld file1.o file2.o'. The difference is that gcc will include the correct system libraries etc for you in the linking, while ld will just create an invalid executable or throw an error. To see exactly what gcc is doing pass it the '-v' option. You will see all the steps gcc does. eg. 'gcc -v helloworld.c' You will see it compile to assembly, then assemble to objects using the 'as' command, then link using 'ld'
gcc is the GNU C compiler and is found at
http://gcc.gnu.org/
ld is part of the 'binutils' package and its homepage is
http://sources.redhat.com/binutils/
Your computer may or may not have gcc installed. type 'gcc -v" on the command line to fine out. If not you will have to install from the CD or the website.