"This is pretty easy. We have a single source file, a few
libraries and a final executable. Scripting the compilation of this
project saves us from having to type that mammoth command line in
every time we make a change to the program.
"But what happens when your project has several, perhaps
hundreds of source files of hundreds or thousands of lines of code
each? Sometimes, it can take several minutes or even hours to
compile a very large project. What if you find an important bug in
your program and have to make this change:?"