Compiling and Linking Programs in Unix

1. linking as a second phase of the compilation command. This is the method most commonly used in the Unix world.
2. compiling and linking with separate commands

   Although a specific command for linking exists ( ld),  in practice it is very little used. Since the compilation command (normally f77)  doesn't require you to actually compile anything and takes care of providing the correct language specific and system libraries, it is usually used for linking in preference to ld.

3. use of the make command 

   The make command is not described here because it involves a completely different philosophy which will only confuse new UNIX users. If you are interested in this powerful tool, you are encouraged to read the man pages for make and the references given there. See also the book by Talbott [10].