[bibtex] Refactor bib-due script

Updated script is a little more resilient, and can be used to filter by
and catch various fields, controlled with a static variable at the top
of the file for now. Still brittle, and breaks easily on bibtex file
changes.

bibtex/.local/bin/bib-due

@@ -0,0 +1,31 @@
+#!/usr/bin/env sh
+# shows due entries of bibtex file passed in
+# HACK: brittle! will break on various bibfile abnormities (even just on due date w/o priority)
+# FIXME: reimplementation with real library needed
+#
+
+fields="due|priority|\bauthor\b|\btitle\b"
+filterby="due"
+
+main() {
+  # use system default bib file or passed argument
+  if [ -n "$1" ]; then
+    file="$1"
+  elif [ -n "$BIBFILE" ]; then
+    file="$BIBFILE"
+  else
+    echo "Requires a bibtex file as argument."
+    exit 1
+  fi
+
+  # filter all entries for those containing filterby field (default: due)
+  # retain values of all fields mentioned in fields variable
+  entries=$(grep -E "^@|$fields" "$file" | awk 1 ORS=' ' | sed -E 's/@\w+\{/\n/g' | grep $filterby | tail -n +2 | sed -E 's/(,\s+(\w+)\s+=\s+|,\s*$)/\t/g' | awk -F'\t' '{ print $4 "\t" $5 "\t" $2 "\t" $3 "\t" $1 }')
+
+  # prettify and sort the entries for display (remove {}, order by date,prio,author,title)
+  entries=$(echo "$entries" | awk -F'\t' '{ gsub(/{/,""); gsub(/}/,""); gsub(/prio/,"",$2) } { print $1 " (" $2 "): " $3 " -- " $4 " (" $5 ")"}' | sort)
+
+  echo "$entries"
+}
+
+main "$@"

bibtex/.local/bin/bib_due

@@ -1,7 +0,0 @@
-#!/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