Zip all folders in current directory and then change their extension.

CreateMangaBook

#!/bin/sh

# Here i is the variable to which foldernames are assigned. %/ removes the trailing / from the filename when zipping
for i in */; do zip -r "${i%/}.zip" "$i"; done

# Rename the above zip files to have the extension .cbr for use with Comic book readers.
for i in *.zip; do mv "$i" "${i%.zip}.cbr"; done