Utility to create skeleton files for new NetKit labs

lmake.sh

#! /bin/bash

# bash >= 4.0 required

[ $# == 0 ] && cat << EOF
Usage: $0 machine[:interface1=hub1[,ip1][:interface2=hub2[,ip2]] ...] ...

Utility to create skeleton files for new NetKit labs. 

Options

machine:   name of a virtual machine
interface: interface number
hub:       collision domain associated to the interface
ip:        IP address associated to the interface

Examples

Three machines a, b, c on three different hubs h0, h1, h2 connected by a router r:
$0 a:0=h0,192.168.0.2 b:0=h1,192.168.1.2 c:0=h2,192.168.2.2 r:0=h0,192.168.0.1:1=h1,192.168.1.1:2=h2,192.168.2.1

EOF

DEBUG="/dev/null"

for m; do
    echo "Parsing $m" >> "$DEBUG"
    declare -A hubs=()
    declare -A ips=()

    if [[ "$m" =~ ^([^:]+):(.+)$ ]]; then
        name="${BASH_REMATCH[1]}"
        options="${BASH_REMATCH[2]}"
        echo "$name has options $options" >> "$DEBUG"
        OLD_IFS="$IFS"
        IFS=":"
        for couple in $options; do
            echo "Couple $couple" >> "$DEBUG"
            if [[ "$couple" =~ ^([0-9]+)=(.+) ]]; then
                interface=${BASH_REMATCH[1]}
                suboptions=${BASH_REMATCH[2]}
                echo "Interface $interface has suboptions $suboptions" >> "$DEBUG"
                if [[ "$suboptions" =~ ^(.+),(.+)$ ]]; then
                    hubs[$interface]=${BASH_REMATCH[1]}
                    ips[$interface]=${BASH_REMATCH[2]}
                    echo "Interface $interface on hub ${hubs[$interface]} at ${ips[$interface]}" >> "$DEBUG"
                else
                    hubs[$interface]=$suboptions
                    echo "Interface $interface on hub $suboptions" >> "$DEBUG"
                fi
            fi
        done
        IFS="$OLD_IFS"
    else
        echo "Name only" >> "$DEBUG"
        name="$m"
    fi
    mkdir -p "$name" &&
    echo -e "#! /bin/sh\n# $name startup script\n" >> "$name.startup"
    for interface in "${!hubs[@]}"; do
        echo -e "$name[$interface]=${hubs[$interface]}" >> "lab.conf"
    done
    for interface in "${!ips[@]}"; do
        echo -e "ifconfig eth$interface ${ips[$interface]}" >> "$name.startup"
    done
    echo -e "# Uncomment the following line to set up a default gateway"  >> "$name.startup"
    echo -e "# route add -net default gw 42.42.42.42" >> "$name.startup"
    echo -e "$name[mem]=64\n" >> "lab.conf"
done