inet_ntoa and inet_aton in pure bash

Do not ask me why, but today I needed a pure implementation of the C-functions inet_aton and inet_ntoa. It’s really not a big deal, but I always have to look up how splitting a string works in bash, and Eris, I so hate the bash manual page, so I cheated and found How do I split a string on a delimiter in Bash? at Stack Overflow.

Never mind, here my code.

function inet_aton () {
    IN=$1
    arrIN=(${IN//./ })
    out=$((${arrIN[0]} << 24))
    out=$(($out ^ ${arrIN[1]} << 16))
    out=$(($out ^ ${arrIN[2]} << 8))
    out=$(($out ^ ${arrIN[3]}))
    echo $out
}

function inet_ntoa () {
    IN=$1
    a=$((IN >> 24 & 0xFF))
    b=$((IN >> 16 & 0xFF))
    c=$((IN >> 8 & 0xFF))
    d=$((IN & 0xFF))
    echo ${a}.${b}.${c}.${d}
}

Simple test:

$ inet_aton 192.168.2.1
3232236033
$ inet_ntoa 3232236033
192.168.2.1

Check inet_aton against the Python implementation:

In [1]: import socket

In [2]: int.from_bytes(socket.inet_aton("192.168.2.1"))
Out[2]: 3232236033

Have fun.