How do i use grep to perform a recursive search in linux?

[shoebill]

Man page for grep.

       -r, --recursive
              Read all files  under  each  directory,  recursively,  following
              symbolic  links only if they are on the command line.  Note that
              if  no  file  operand  is  given,  grep  searches  the   working
              directory.  This is equivalent to the -d recurse option.

       -R, --dereference-recursive
              Read  all  files  under each directory, recursively.  Follow all
              symbolic links, unlike -r.

$ cd directory_to_search
$ grep -r 'text_to_search'