Post-install script for Jetson Nano

jetson-nano-post-install.sh

#! /usr/bin/env bash
#
# This is a custom post-install script for a Jetson Nano.
#
set -ex

me=$(whoami)
if [ "$me" != "root" ]
then
    echo 'Must run as root!'
    exit 1
fi >&2

main() {
    trim
    update
    apt install mc atop htop lsof strace arj links lynx tmux screen mosh mtr nmap ndiff dstat sysstat python3.8-venv

    mkdata /dev/mmcblk0

    sudonopass

    user=$(firstuser)
    usermod --append --groups docker $user

    shutdown -r now
}

trim() {
    apt remove gconf2 whoopsie
    systemctl stop gdm3
    systemctl set-default multi-user
    if [ -e /etc/update-motd.d/60-unminimize ]
    then unminimize #TODO: carefully handle prompts
    fi
}

update() {
    apt update
    apt dist-upgrade
}

sudonopass() {
    if ! egrep '^%sudo.+NOPASSWD:' /etc/sudoers
    then perl -i -pe 's/^(%sudo\s.+)/#$1\n# Same thing without a password\n%sudo ALL=(ALL:ALL) NOPASSWD: ALL/' /etc/sudoers
    fi
}

firstuser() {
    awk -F: '$3==1000&&$4==1000{print $1}' /etc/passwd
}

mkdata() {
    local dev="$1"
    local free=$(getfree $dev)
    local start="${free%B *}"
    local diskend="${free#*B}"
    diskend="${diskend::-1}"
    test "$diskend" ||return 0

    # create a 4GB swap
    if ! grep "$dev" /proc/swaps
    then
        local end=$[start +4*1024*1024*1024 -1]
        parted "$dev" mkpart primary linux-swap "${start}B" "${end}B"
        local num=$(getlast $dev)
        parted "$dev" name "$num" swap
        mkswap "${dev}p$num" ||:
        echo "${dev}p$num swap swap defaults" >>/etc/fstab
    fi

    # and remaining space as /data
    if [ ! -e /data ]
    then
        parted "$dev" mkpart primary ext4 "$[end+1]B" "${diskend}B"
        num=$(getlast $dev)
        parted "$dev" name "$num" DATA
        mkfs.ext4 -e remount-ro -LDATA -m1 -i32768 "${dev}p$num"
        mkdir -p /data
        echo "${dev}p$num /data ext4 defaults 0 2" >>/etc/fstab
    fi
}

getfree() {
    parted "$1" unit B print free |awk '
        NF >3 {
            start= ""
            end= ""
        }
        /Free Space/ {
            start= $1
            end= $2
        }
        END {
            print start, end
        }'
}
getlast() {
    parted "$1" print |awk '
        NF >3 {
            num= $1
        }
        END {
            print num
        }'
}

main "$@"
exit 0