#!/bin/bash

[[ -z $1 ]] && print \$1 missing && exit 1
[[ ! -f /usr/share/ieee-data/oui.txt ]] && echo /usr/share/ieee-data/oui.txt needs to be available && exit 1

mac=`echo $1 | sed -r 's/://g; s/(......).*/\1/'`

grep -i $mac /usr/share/ieee-data/oui.txt