converting pdf to png, works on multipage PDF

convert.bash

#!/bin/bash

for file in *; do
        if [ ${file: -4} == ".pdf" ]
        then
                echo "Converting $file using ghost script..."
                # Handle multi pages
                gs -sstdout=%stderr -dPDFSTOPONERROR -dNOPAUSE -sDEVICE=pngalpha -o $file-%03d.png -r600 $file
                if [ "$?" != "0" ]
                then
                        # ghost script may returns error for some PDF files. Use inkscape as failsafe.
                        echo "Converting $file using inkscape..."
                        inkscape "$file" -z --export-dpi=600 --export-area-drawing --export-png="$file.png"
                fi
        fi
done

echo "Done."