clean_minimal_ubuntu.sh

#!/bin/bash

apt install --no-install-recommends systemd-cron ifupdown

# Step: Cleanup 1
apt purge -y popularity-contest \
    laptop-detect os-prober \
    snapd flatpak libflatpak0 \
    lxd lxd-client lxcfs lxc-common \
    language-selector-common ^language-pack-.* \
    installation-report \
    screen byobu \
    open-iscsi \
    update-manager-core update-notifier-common \
    accountsservice \
    dictionaries-common emacsen-common wamerican wbritish \
    at \
    ufw \
    overlayroot \
    ubuntu-advantage-tools \
    wireless-regdb \
    ubuntu-release-upgrader-core \
    landscape-common \
    plymouth \
    libx11-data \
    nano \
    ^libntfs-3g.* dosfstools \
    linux-firmware ^linux-generic.* ^linux-headers.* \
    xdg-user-dirs \
    netplan.io networkd-dispatcher \
    tmux htop mc
apt autoremove --purge -y

###############################################################

# STFU MOTD-NEWS
systemctl stop motd-news.timer
systemctl stop motd-news.service
systemctl disable motd-news.timer
systemctl disable motd-news.service
echo -e "ENABLED=0" > /etc/default/motd-news

###############################################################

# Step: InitRamFS - ZSWAP LZ4 compressor
grep -q -w 'lz4' /etc/initramfs-tools/modules || echo lz4 >> /etc/initramfs-tools/modules
grep -q -w 'lz4_compress' /etc/initramfs-tools/modules || echo lz4_compress >> /etc/initramfs-tools/modules
update-initramfs -u

# Step: Bootloader - ZSWAP
grep -v '#' /etc/default/grub | grep -w 'GRUB_CMDLINE_LINUX=' | tail -n 1 > /tmp/grub.cmdline
echo -e "GRUB_DEFAULT=0
GRUB_TIMEOUT=5
GRUB_DISTRIBUTOR=\`lsb_release -i -s 2> /dev/null || echo Debian\`
GRUB_CMDLINE_LINUX_DEFAULT=\"zswap.enabled=1 zswap.compressor=lz4\"
GRUB_TERMINAL=console
GRUB_DISABLE_OS_PROBER=true" > /etc/default/grub
cat /tmp/grub.cmdline >> /etc/default/grub
rm -f /tmp/grub.cmdline
update-grub

###############################################################

echo "[Unit]
Description=Generate New Machine ID
DefaultDependencies=no
Conflicts=shutdown.target
After=systemd-remount-fs.service
Before=systemd-sysusers.service sysinit.target shutdown.target systemd-journald.service
ConditionPathIsReadWrite=/etc

[Service]
Type=oneshot
RemainAfterExit=yes
ExecStartPre=-/bin/rm -f /var/lib/dbus/machine-id
ExecStartPre=-/bin/rm -f /etc/machine-id
ExecStart=/bin/systemd-machine-id-setup

[Install]
WantedBy=basic.target" > /etc/systemd/system/systemd-machine-id-setup.service
systemctl daemon-reload
systemctl enable systemd-machine-id-setup.service

###############################################################

# Step: Cleanup 2
apt autoremove --purge -y

# Step: upgrade
apt full-upgrade -y

## Step: cleanup 3
# Unattended-upgrades
rm -f /etc/apt/apt.conf.d/20auto-upgrades.ucf-dist
rm -f /etc/apt/apt.conf.d/50unattended-upgrades.ucf-dist

# APT
apt clean
rm -f /var/lib/apt/lists/*/* 2> /dev/null
rm -f /var/lib/apt/lists/* 2> /dev/null

# DHCP
rm -rf /var/lib/dhcp/* 2> /dev/null

# DBUS
rm -rf /var/lib/dbus/* 2> /dev/null

# Logrotate
rm -rf /var/lib/logrotate/* 2> /dev/null

# Urandom
rm -rf /var/lib/urandomdev/null

# Supervise
rm -rf /var/lib/supervise

# update-manager
rm -rf /var/lib/update-manager

# release-upgrader
rm -rf /var/lib/ubuntu-release-upgrader

# Journal (if any)
rm -rf /var/log/journal/* 2> /dev/null

# LOGs
rm -f /var/log/*/* 2> /dev/null
rm -f /var/log/* 2> /dev/null

touch /var/log/lastlog
chown root:utmp /var/log/lastlog
chmod 0664 /var/log/lastlog

touch /var/log/dmesg
chown root:adm /var/log/dmesg
chmod 0640 /var/log/dmesg

touch /var/log/faillog
chown root:root /var/log/faillog
chmod 0644 /var/log/faillog

# sync
sync