Bash script to list all IPs in prefix

Question

I\'m trying to create script that I can input a set of prefixes, which will then list all IP addresses within the prefixes (including network/host/broadcast).

An ex

Answer 1

I think this little script I hacked together does the trick. If not, it's definitely a starting point! Good luck.

#!/bin/bash                                                                                                                                                                                                                                                              

############################                                                                                                                                                                                                                                             
##  Methods                                                                                                                                                                                                                                                              
############################                                                                                                                                                                                                                                             
prefix_to_bit_netmask() {
    prefix=$1;
    shift=$(( 32 - prefix ));

    bitmask=""
    for (( i=0; i < 32; i++ )); do
        num=0
        if [ $i -lt $prefix ]; then
            num=1
        fi

        space=
        if [ $(( i % 8 )) -eq 0 ]; then
            space=" ";
        fi

        bitmask="${bitmask}${space}${num}"
    done
    echo $bitmask
}

bit_netmask_to_wildcard_netmask() {
    bitmask=$1;
    wildcard_mask=
    for octet in $bitmask; do
        wildcard_mask="${wildcard_mask} $(( 255 - 2#$octet ))"
    done
    echo $wildcard_mask;
}



#######################                                                                                                                                                                                                                                                  
##  MAIN                                                                                                                                                                                                                                                                 
#######################                                                                                                                                                                                                                                                  
for ip in $@; do
    net=$(echo $ip | cut -d '/' -f 1);
    prefix=$(echo $ip | cut -d '/' -f 2);

    bit_netmask=$(prefix_to_bit_netmask $prefix);

    wildcard_mask=$(bit_netmask_to_wildcard_netmask "$bit_netmask");

    str=
    for (( i = 1; i <= 4; i++ )); do
        range=$(echo $net | cut -d '.' -f $i)
        mask_octet=$(echo $wildcard_mask | cut -d ' ' -f $i)
        if [ $mask_octet -gt 0 ]; then
            range="{0..$mask_octet}";
        fi
        str="${str} $range"
    done
    ips=$(echo $str | sed "s, ,\\.,g"); ## replace spaces with periods, a join...                                                                                                                                                                                        
    eval echo $ips | tr ' ' '\012'

done