## Header contains non-printing characters, so this is more
## reliable than using awk.
cat <"${1?}" || exit
test $# -ge 2 || exit 1
cat <"$1"
shift
exec "${AWK-awk}" '
if (data[dircat])
printf "\n%s\n%s", topic[dircat], data[dircat]
}
' "${@?}"
' "$@"
-