How can I run ctags in a large code base?

Question

Assuming I have a code directory structure as follows:

/top  
   /second  
       /core  
           a.pl  
           b.pl  
           c.pl  
       /common  
           d.pl  
           e.pl  
       /util  
           f.pl  
           g.pl  
           h.pl    

Where should I run the ctags so that I can jump to function definitions via vi?

For example I had:

/dir
   /perl  
      a.pl  

and I run in dir the command ctags -R perl but in a.pl I could not jump to a function definition that existed in the same file.
If I did ctags -R . inside the perl directory it worked.

So I can not understand the pattern. Should I run ctags in core, common,util? What if my code base is huge? Would I really need to run it in each directory?

Answer 1

Your tags file should be generated in the first common ancestor of your code (that would be second, in your case) with $ ctags -R ..

I'd suggest you add this line to your ~/.vimrc in order to make Vim always find your tags file, no matter where you are in your project and no matter what the "current directory" is:

set tags=./tags;/,tags;/

It works like the one in @glts's answer with an interesting twist: because of the ;/ part, Vim looks up and up until / for a tags file. Supposing you are editing g.pl, Vim will correctly use your tags file located in second.

:h tags
:h ctags