====== Daily Regular Expresssion ======

==== Grab IP ====
<code bash>
egrep '([[:digit:]]{1,3}\.){3}[[:digit:]]{1,3}'
</code>
<code bash>
grep '^[0-9]\{1,3\}\.[0-9]\{1,3\}\.[0-9]\{1,3\}\.[0-9]\{1,3\}$'
</code>
<code bash>
cat textfile | grep -o '[0-9]\{1,3\}\.[0-9]\{1,3\}\.[0-9]\{1,3\}\.[0-9]\{1,3\}'
</code>
<code bash>
/sbin/ifconfig | grep "inet addr" | awk -F : '{print $2}' | awk '{print $1}' | grep -v -e '^192.\|^127.\|^10.'
</code>