#!/bin/awk -f
#
# Simple awk script to obtain list of ip address v. mac address from
# /etc/ethers.  It ignores all lines starting with '#' and only outputs
# anything for hosts with a corresponding entry in /etc/hosts.  The
# output is suitable for the RARPD.TBL needed by Lew Perin's RARPD. To
# use:
#
#    rarpd.awk /etc/ethers > RARPD.TBL
#

BEGIN {
    FS = "[ \t:]+";
    n = 0;
    while( getline < "/etc/hosts" ) {
        host[n] = $2;
        addr[n] = $1;
        n++;
    }
}

function lookupHost( h ) {
    for( i = 0; i < n; i++ ) {
        if( host[i] == h ) { return addr[i]; }
    }
    return "0.0.0.0";
}

/^[^\#]/ {
    ip = lookupHost($7);
    if( ip != "0.0.0.0" ) {
        printf( "%s.%s.%s.%s.%s.%s %s\n", $1, $2, $3, $4, $5, $6, ip );
    }
}