Редактор nano более дружелюбен (sudo apt-get install nano, если он недоступен).
echo "<Directory \"/var/www/*\">" > out_file
echo " Order allow,deny" >> out_file
echo " Allow from all" >> out_file
echo " AllowOverride All" >> out_file
echo "</Directory>" >> out_file
cat out_file | sudo tee -a /etc/apache2/apache2.conf