$ sudo apt-get install libchm-bin
$ extract_chmLib book.chm outdir
book.chmis the path to your CHM file and
outdiris a new directory that will be created to contain the HTML extracted from the CHM file.
After running the utility to extract the HTML files from your CHM file, the extracted files will appear in
. There won’t be an “index.html” file, unfortunately. So you’ll have to inspect the filenames and/or their contents to find the appropriate main page or Table of Contents.
Now the HTML is yours to enjoy!