User:Covracer

Graphics Magick Alternating Rotation in Bash

for p in p000[1-9].pnm p001?.pnm p002[0-3].pnm; do
  pageno=$(echo $p | sed -r 's/p0*([1-9][0-9]*)\.pnm/\1/')
  angle=90
  [[ $(($pageno % 2)) -eq 1 ]] && angle=-90
  gm mogrify -rotate $angle $p
done

Graphics Magick TIFF to PNG Conversion in Bash

for p in 000[1-9].tiff 001?.tiff; do
  page=${p/.tiff/}
  pageno=$(echo $page | sed s/0//g)
  angle=90
  [[ $(($pageno % 2)) -eq 1 ]] && angle=-90
  echo $p; gm convert $p -geometry 75% -rotate $angle Page\ $page\ \(4-Valve\ Engine\,\ Russell\,\ 1901\).png
done