tags is a utility, closely associated with (but not, AFAIK, restricted to use with) vi and vim, "VI iMproved".

The basic concept's pretty simple, when you run tags on a C source file, it will catalog all your functions and variables (and basically, anything else you can give a name to in C or C++) for you, which makes it easier down the road to debug your code (was hit_count an int or a long? In vi/ vim, run tags and it will save your current place and take you to the file and place in that file where you defined hit_count.)

Fire up vi or vim, and type in :help tags for how ta use it. Emacs *must* have a facility for working with tags, but it will take an infidel to fill you in on that =)

I've heard tell that Tom Christiansen wrote such a utility for use with Perl code, but it wasn't in the place I looked for it.

Philosophy can be made out of anything. Or less -- Jerry A. Fodor