Alas, in addition to having no recursive option in /usr/bin/grep, Solaris also offers the inability to use /usr/bin/find and /usr/bin/xargs like this:

  find . -print0 -type f | xargs -0 grep -li search_term
[download]

at least, not in SunOS 5.8 -- I don't know if this has been fixed in more recent releases, but if it hasn't... well, I just don't understand what's wrong with those people at Sun.

Solaris users generally benefit from having the GNU tools installed in /usr/local/bin, and putting that in front of /usr/bin in their shell PATH.