Disabling the anti-aliasing for a specific font with user's fonts.conf

Solution 1:

[I know this question is 5 years old, but it still appears in search engines.]

I just made a .fonts.conf file in the Home directory. It worked right away in Ubuntu 18.04 LTS.

(Replace the font names accordingly!)

<!-- 
~/.fonts.conf

Remember to run "fc-cache" after you modify this file.
-->

<fontconfig> 

  <match target="font">
    <test name="family" qual="any">
      <string>Ubuntu Mono</string>
      <string>Free Pixel</string>
    </test>
    <edit name="antialias" mode="assign">
      <bool>false</bool>
    </edit>
  </match>

</fontconfig>

I put it into a Gist, plus some additional documentation just in case: https://gist.github.com/gonzalocesar/7ef41572a2627b65da976001a29ba7ee