File prepare_tar of Package surfer-gallery

#!/bin/sh -ex

wget -c http://data.imaginary2008.de/software/surfer/surfer.tar.bz2

rm -Rf surfer;
mkdir -p surfer;
pushd surfer;
tar -xvf ../surfer.tar.bz2 gallery.tar;
tar -xvf gallery.tar;
rm -f gallery.tar;
find gallery* -type f -name "*.png" -exec optipng '{}' '+';
tar --use=xz -cf ../gallery.tar.xz gallery*;
popd;
rm -Rf surfer;