heavy overhaul: Better communication, option to only clean one file, adding backups and directory independency

pdf-clearmeta.sh

@@ -1,7 +1,9 @@
 #!/bin/bash
 
 # A very simple script by Max Mehl: mail@mehl.mx
-# Removes all metadata from a PDF file located in the same dir like the script
+# Removes all PDF metadata from 
+#   a) all PDF files in a directory
+# 	b) or one file given as parameter
 # This happens by the usage of pdftk, a powerful command line tool on GNU/Linux
 
 # change to directory where the script resides if tool is called by cron