def address
return @mac_address if defined? @mac_address and @mac_address
re = %r/[^:\-](?:[0-9A-F][0-9A-F][:\-]){5}[0-9A-F][0-9A-F][^:\-]/io
cmds = '/sbin/ifconfig', '/bin/ifconfig', 'ifconfig', 'ipconfig /all'
null = test(?e, '/dev/null') ? '/dev/null' : 'NUL'
lines = nil
cmds.each do |cmd|
stdout = IO.popen("#{ cmd } 2> #{ null }"){|fd| fd.readlines} rescue next
next unless stdout and stdout.size > 0
lines = stdout and break
end
raise "all of #{ cmds.join ' ' } failed" unless lines
candidates = lines.select{|line| line =~ re}
raise 'no mac address candidates' unless candidates.first
candidates.map!{|c| c[re].strip}
maddr = candidates.first
raise 'no mac address found' unless maddr
maddr.strip!
maddr.instance_eval{ @list = candidates; def list() @list end }
@mac_address = maddr
end