/usr/bin/libnet-config is in libnet1-dev 1.1.6+dfsg-2ubuntu1.
This file is owned by root:root, with mode 0o755.
The actual contents of the file can be viewed below.
1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60 61 62  | #!/bin/sh
#
#   $Id: libnet-config.in,v 1.3 2004/01/03 20:31:00 mike Exp $
#
#   Libnet 1.1 libnet-config compilation script
#   (c) 1998 - 2004  Mike D. Schiffman <mike@infonexus.com>
#
#   libnet-config.  Generated from libnet-config.in by configure.
libnet_defines="-D_BSD_SOURCE -D__BSD_SOURCE -D__FAVOR_BSD -DHAVE_NET_ETHERNET_H"
libnet_cflags=""
libnet_libs=" -lnet"
usage()
{
        cat <<EOF
Usage: libnet-config [OPTIONS]
Options:
        [--libs]
        [--cflags]
        [--defines]
EOF
        exit
}
while test $# -gt 0; do
    case "$1" in
    -*=*) optarg=`echo "$1" | sed 's/[-_a-zA-Z0-9]*=//'` ;;
    *) optarg= ;;
    esac 
    case $1 in
        --libs)
            echo_libs=yes
            ;;
        --cflags)
            echo_cflags=yes
            ;;
        --defines)
            echo_defines=yes
            ;;
        *)
            usage 1
        esac
    shift
done
if test "$echo_libs" = "yes"; then
    echo $libnet_libs
fi
if test "$echo_cflags" = "yes"; then
    echo $libnet_cflags
fi
if test "$echo_defines" = "yes"; then
    echo $libnet_defines
fi
# EOF
 |