Warning: this is an htmlized version!
The original is across this link,
and the conversion rules are here.
#!/bin/sh
# (find-angg ".fvwm/edrx-menus.fvwm")
# (find-angg ".zshrc" "myincr")
# (find-man "1 xwd")
# (find-man "1 convert")

mkdir -p   /tmp/screenshots
cd         /tmp/screenshots || exit 1

if [ ! -e n ]; then 
  echo 0 > n
fi

N=$[$(<n)+1]
xwd | convert - ss$(printf %02d $N).png
echo $N > n