I suggest redirecting the results into a cachefile, because the extraction is pretty slow.
srcsysmod_kmod() { tab="$(printf "\t")" ( cd /usr/src/sys/modules find . -type f -name 'Makefile' | sed -e 's#^\./##' | xargs dirname | sort | while read dir do makefile="${dir}/Makefile" kmod="$(cat "${makefile}" | egrep '^KMOD' | sed -e "s/^KMOD[ ${tab}]*=[ ${tab}]*//" )" [ "${kmod}" ] && echo "${dir}${tab}${kmod}" done ) }