<elliott> addquote <olsner> combining macros and templates can get horrible... macro(foo<bar,baz>) is two macro arguments, for instance <olsner> variadic macros can work part-way around that though <olsner> the kind of workaround where you end up inside the wall instead of on the other side of the problem

#!/bin/sh
cd /var/irclogs/_esoteric
if [ "$1" ]; then
    grep -P -i -- "$1" ????-??-??.txt | shuf -n 1
else
    file=$(shuf -en 1 ????-??-??.txt)
    echo "$file:$(shuf -n 1 $file)"
fi