dejavu-fonts/dejavu-fonts-persian-override.conf

<?xml version="1.0"?>
<!DOCTYPE fontconfig SYSTEM "fonts.dtd">
<!-- /etc/fonts/conf.d/00-dejavu-persian-override.conf

     Override DejaVu use in Persian

     © 2006 Nicolas Mailhot <nicolas.mailhot at laposte.net>
     This file is distributed under the terms of the GNU General
     Public License (GPL) version 2. Copies of the GPL can be obtained from:
     http://www.gnu.org/licenses/gpl.html
-->
<fontconfig>
  <match>
    <test name="family"><string>DejaVu Sans</string></test>
    <test name="lang"><string>fa</string></test>
    <edit name="family" mode="assign" binding="same">
      <string>Roya</string>
    </edit>
  </match>
  <match>
    <test name="family"><string>DejaVu Serif</string></test>
    <test name="lang"><string>fa</string></test>
    <edit name="family" mode="assign" binding="same">
      <string>Nazli</string>
    </edit>
  </match>
  <match>
    <test name="family"><string>DejaVu Sans Mono</string></test>
    <test name="lang"><string>fa</string></test>
    <edit name="family" mode="assign" binding="same">
      <string>Terafik</string>
    </edit>
  </match>
</fontconfig>