# Perl version

while (<>){              # Loop over the input file/stream
    my @line = split;    # Split each line into "fields"
    next unless $line[1] =~ /^[AP]M$/ && $line[2] =~ /^(eth|bon)/;

    # Note: the 'eth0' and the 'IFACE' line aren't in here because they don't
    # contribute anything to the validation routine as originally written.
    
    [ ... ]