[script] Add simple due script for bibtex file

Scrapes a bibtex file for 'due' field, and outputs all found entries
with their priority and sorted for date.

bibtex/.local/bin/bib_due

@@ -0,0 +1,7 @@
+#!/usr/bin/env sh
+# shows due entries of bibtex file passed in
+# HACK: brittle and hacky!
+#
+# looks for 'due' entries in bibfile and gets their
+
+awk '/due|^@\w|prio[123]/' ORS=' ' "$1" | sed -E 's/ (@\w)/\n\1/g' | grep due | sed 's/ //g' | sed -E 's/^@\w+\{(\w+),due=\{(.+?)\},.*,priority=\{(\w)+\}.*$/\2 \3 \1/' | sort