How do I get the explanation of gcc -s?

From man gcc:

   -s  Remove all symbol table and relocation information from the
       executable.

I found this by searching for "-s" (note leading and trailing space) in the man pager.

On man gcc only more used and useful options are listed. The rest of documentation can be found on gcc online web page

From: http://gcc.gnu.org/onlinedocs/gcc/Link-Options.html#Link-Options

-s Remove all symbol table and relocation information from the executable.