Bash - export SVGs to PNGs with Inkscape

#!/bin/sh
# Script for exporting SVGs to PNGs with Inkscape.
# Based on code found in:
# http://askubuntu.com/questions/209449/is-there-a-way-to-batch-export-svgs-to-pngs

# for each file ending with .svg
for file in *.svg
do
    # strip the .svg part and save output as $filename
    filename=`echo "${file}" | sed s/.svg//`

    # export current file to .png
    /usr/bin/inkscape -z -f "${file}" -w 640 -e "$filename.png"
done