Solid State Raam » Bash http://solidstateraam.com Explorations (and exploitations) of the digital world by one of its many netizens. Sat, 17 Dec 2011 20:18:47 +0000 en hourly 1 http://wordpress.org/?v=3.3 MAC Address Validation Regex with egrep http://solidstateraam.com/mac-address-validation-regex-with-egrep/ http://solidstateraam.com/mac-address-validation-regex-with-egrep/#comments Thu, 27 Aug 2009 00:45:08 +0000 Raam http://solidstateraam.com/?p=334 I needed an easy way to validate a MAC address in a bash script that generated a unique hostname based on the MAC address of the system. This gem did the trick:

echo "00:11:24:3e:a5:78" | egrep "^([0-9a-fA-F]{2}\:){5}[0-9a-fA-F]{2}$"

In the event that there was a problem getting the MAC address (e.g., faulty NIC or unstable device driver), I generate a random hostname instead of basing the hostname generation on the MAC. Here’s how I validated the MAC in the script:

if [ `echo $ACTIVE_INTERFACE_MAC | egrep "^([0-9a-fA-F]{2}\:){5}[0-9a-fA-F]{2}$"` ]; then
	# generate unique hostname based on MAC
else
	# generate random-character hostname
fi
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