It’s not bash itself that was the complex part exactly, but I have a CI/CD pipeline that generates epub files from markdown. In some cases I have custom designed covers, but where a cover doesn’t exist I have a bash script generate one using Imagemagick.

I wanted to generate the cover in one command to lessen performance impacts and disk I/O, but it took me a few weeks to figure out how to do it all in a single Imagemagick command:

convert \
    -size 960x1536 \
    -background "${backgroundColor}" \
    -fill "${textColor}" \
    -font "Liberation-Serif" \
    -pointsize 96 \
    -gravity north \
    caption:"${title}" \
    -bordercolor "rgb(0, 0, 0)" \
    -border 2 \
    -bordercolor "${borderColor}" \
    -border 40 \
    -background none \
    -fill "${textColor}" \
    -font "Liberation-Serif" \
    -pointsize 48 \
    -gravity south \
    -geometry +0-800 \
    -annotate +0+40 "${author}" \
    "${destination}cover.jpg"

Eventually it made an abstract sense to me, and I was able to bring it down to two commands and then finally one. This generates a cover with a selected background color (based on content type) and contains title text that will wrap to an inner border.

I think I had to give up on the author being wrapped, but it’s much smaller than the title anyway.