Options +FollowSymlinks
Options -Indexes
RewriteEngine On
RewriteBase /
RewriteCond %{HTTP_HOST} ^www.(.*)$ [NC]
RewriteRule ^(.*)$ http://%1/$1 [R=301,L]

<VirtualHost *:80>
  ServerAdmin info@example.com
  ServerName  m.example.com
  ServerAlias m.example.com

  DirectoryIndex default.php index.php
  DocumentRoot /var/www/example/public_html/m/
  LogLevel warn
  ErrorLog  /var/www/example/log/error.log
  CustomLog /var/www/example/log/access.log combined
</VirtualHost>

<VirtualHost *:80>
  # Admin email, Server Name (domain name), and any aliases
  ServerAdmin info@example.com
  ServerName  example.com

  # Index file and Document Root (where the public files are located)
  DirectoryIndex default.php index.php
  DocumentRoot /var/www/example/public_html
  # Log file locations
  LogLevel warn
  ErrorLog  /var/www/example/log/error.log
  CustomLog /var/www/example/log/access.log combined
</VirtualHost>