#!/usr/bin/perl
#
# Read arp -a output and emit /etc/ethers format.
#	- Cameron Simpson <cs@zip.com.au> 01sep1995
#

($cmd=$0) =~ s:.*/::;

$xit=0;
ARP:
while (<>)
{ chomp;
  #     if     host     ether
  if (/^\w+\s+([-\w]+)\s.*([\da-f]{2}(:[\da-f]{2}){5})$/)
  { ($host,$ether)=($1,$2);
  }
  #         host                                    ether
  elsif (/^([-\w]+)\.$ENV{MAILDOMAIN}\s.*at\s+([\da-f]{2}(:[\da-f]{2}){5})$/o)
  { ($host,$ether)=($1,$2);
  }
  else
  { warn "$cmd: warning: $ARGV, line $.: bad format: $_\n";
    $xit=1;
    next ARP;
  }

  ## $ether =~ s/\b0+([\da-f]+)/$1/g;
  print "$ether\t$host\n";
}

exit $xit;