Linux commands I find usefull.
free -m
( show free memory )
htop
sync; echo 3 > /proc/sys/vm/drop_caches
(clears cache from ram)
top -b -n 1 | grep -i apache
( shows apache memory consumption)
df -h
(free disk space)
sudo useradd testuser -p testpass -d /var/www/vhosts/tvshow.com/
dscacheutil -flushcache
sudo nano /private/etc/hosts
Virtual Hosts Examples:
http://httpd.apache.org/docs/2.2/vhosts/examples.html
Vhosts:
http://articles.slicehost.com/2010/5/19/apache-virtual-hosts-on-centos-part-1