last time a full update of pdf will be done.

find_stale_pdf.bash

@@ -0,0 +1,28 @@
+#!/bin/bash
+file_list=`find . -print | grep -i ".md"`
+
+for element in $file_list
+do
+	dir=`dirname ${element}`
+	cd $dir
+	md_name=`basename ${element} .md`
+    pdf_name=${md_name}.pdf
+    md_name=${md_name}.md
+    if [ ! -f $pdf_name ]
+    then
+        echo Generating missing PDF file in $dir for $md_name
+        pandoc $md_name -o $pdf_name
+        cd - > /dev/null
+        continue
+    fi
+    md_date=`date -r ${md_name} +%s`
+    pdf_date=`date -r ${pdf_name} +%s`
+    if [ $pdf_date -lt $md_date ];
+    then
+        #echo Is $pdf_date greater than $md_date 
+        echo Freshening $pdf_name in $dir
+        pandoc $md_name -o $pdf_name
+    fi 
+	cd - > /dev/null
+done
+