I have received the following error message when using your tool on a Ubuntu 18.04.3 machine with only python3 installed:

  File "/usr/bin/chm2pdf", line 341
    print '### WARNING: ' + options['titlefile'] + ' not found inside ' + filename + ' - possible spelling error.'
SyntaxError: Missing parentheses in call to 'print'. Did you mean print('### WARNING: ' + options['titlefile'] + ' not found inside ' + filename + ' - possible spelling error.')?

As a workaround, I propose to update the shebang by explicitly stating the python version that is required, i.e., python2.7

The problem is right here. I have a bunch of CHM files from a Windows machine and this script is failing with shell syntax errors.

This could be a security bug if chm2pdf is used as part of another script that accepts untrusted filenames. A string like my_file; rm -rf $HOME .chm is a legal Unix filename, and would result in unexpected code execution if it was encountered by chm2pdf.

What if this site is using this script in its implementation?

Fortunately, the fix is easy.