# tex4ebook error: unable to convert to number

I tried to run tex4ebook on the same MWE of this question (actually I tried also with a much more complex source, getting the same problem)

\documentclass{article}
\usepackage[utf8]{inputenc}
\usepackage[T1]{fontenc}
\begin{document}
\section{section 1}
this is a test

\end{document}


with

tex4ebook test.tex -format epub3 -shell-escape


and I got the following error:

tex4ebook:unable to convert to number: -m


I just updated with tlmgr update --self --all --reinstall-forcibly-removed my TexLive 2016 Windows distribution (which updated tex4ht among others), and htlatex works correctly on my system. For example, running

htlatex test.tex "xhtml,charset=utf-8,fn-in,3,next,mouseover" " -cunihtf -utf8"


produces the expected xhtml file.

Any clue?

You can use two formats to pass options to tex4ebook, short and long names. Short options begin with one -, while long options begin with --. The problem in your case is that you want to use long names, but you start them with just one -, so tex4ebook tries to recognize them as as short ones.

You should either use

tex4ebook  --format epub3 --shell-escape test.tex


as long options, or

tex4ebook  -sf epub3 test.tex


for short options. As you can see, you can collapse multiple short options into one.

• About the double -- I guess you might want to fix the documentation on CTAN ( mirrors.ctan.org/support/tex4ebook/tex4ebook-doc.pdf ), since from that PDF seems that also the full length option version (like format) should be called with a single -. I guess Tex replaced the double dash with a single longer dash. – mmj Jul 31 '16 at 19:16
• you are right, I've missed that. it is indeed the issue that double hyphen is replaced with dash – michal.h21 Jul 31 '16 at 19:38

The problem is with the syntax you are using. Instead of:

tex4ebook test.tex -format epub3 -shell-escape


tex4ebook --format epub3 -s test.tex