Generate dynamic hostname based on hwaddr and aspell dict

generate_hostname.sh

#!/bin/bash

out_of_bounds() {
    local num=$1 max=$2

    while [ $num -gt $max ]; do
        num=$(( $num - $max ))
    done
    echo $num
}

generate_hostname() {
    local hwaddr=$1

    # Generate dictionary
    aspell dump master | sed -e "s/\W//g" -e 's/\(.*\)/\L\1/' >$TMPFILE
    max=$(cat $TMPFILE | wc -l)

    # Strip out hwaddr separator
    stripped=${hwaddr//[:-]/}

    # Split hwaddr in two parts
    part1=${stripped:0:6}
    part2=${stripped:6:6}

    # Convert hex to a dec number
    num1=$((16#${part1}))
    num2=$((16#${part2}))

    # Fix number if it's out of bounds
    num1=$(out_of_bounds $num1 $max)
    num2=$(out_of_bounds $num2 $max)

    # Lookup word in dictionary
    word1=$(tail -n+$num1 $TMPFILE | head -n1)
    word2=$(tail -n+$num2 $TMPFILE | head -n1)

    printf '%s-%s' $word1 $word2
}

TMPFILE='/tmp/aspell_dict'

hwaddr=$(cat /sys/class/net/eth0/address)
echo $(generate_hostname $hwaddr)