I have several Perl scripts which I find useful when working with Fortran programs. Most are more fully documented in the SPEM manual (available from me) and all have descriptive comments in their header.

The first group modifies your source code:

Note - these usually work on the kind of Fortran I write, but they have been known to do the wrong thing. DO NOT DELETE YOUR ORIGINAL CODE BEFORE CHECKING THE NEW CODE.
I also have tools for building Fortran makefiles using the X11 imake program and a Perl5 makedepend script.
These Perl slides were originally from Tom Christiansen. I have converted them to the LaTeX seminar style and added a few Perl 5 slides. These slides are from a short talk I gave about regular expressions, based on the Perl man pages.