ArchLinux USB install script

#!/bin/bash
##=============================  mk-usb  =============================##
# mk-usb <DEVICE>
# Automated Arch Linux USB install:
#  * for use with 16GB USB stick
#  * creates two bootable host OS partitions
#  * OS partitions load completely to RAM by default with ramroot
#  * enabled large page memory support for mining
#  * tweaked journaling for running OS from a USB
#  * reverted to traditional network device naming
#  * disabled terminal bell
#  * added custom repo to /etc/pacman.conf
#  * set NOPASSWD for various user commands
#  * various other tweaks
# Partition scheme:
#  * sdx1        10M
#  * sdx2  vfat  500M
#  * sdx3  ext4  $HOME_SIZE
#  * sdx4  ext4  $HOST1_SIZE
#  * sdx5  ext4  [remaining]
# Mount scheme:
#  * sdx4/sdx5       /
#  * sdx3            /home
#  * sdx2            /EFI
#  * /EFI/$HOSTNAME  /boot

##===========================  VARIABLES  ============================##
SCRIPT_DIR="$( cd "$( dirname "${BASH_SOURCE[0]}" )" && pwd )"
# HOST/USER settings:
HOME_SIZE='1G'
HOST_KEYMAP='/usr/share/kbd/keymaps/i386/qwerty/us.map.gz'
HOST_LANG='en_US.UTF-8'
HOST_TIMEZONE='America/Chicago'
ROOT_PASS='xxxxxxx'
USER_COMMANDS_NOPASS=('ALL')
USER_NAME='bikes-n-math'
USER_PASS='xxxxxxx'
HOST_PKGS_COMMON=(
    base
    base-devel
    pacman-contrib
    sudo
    acpi
    arch-install-scripts
    arch-wiki-lite
    bc
    binwalk
    cifs-utils
    cmake
    curl
    dialog
    dmidecode
    dosfstools
    efitools
    efivar
    elinks
    exfat-utils
    fbida
    figlet
    fuse2
    fuse3
    fuseiso
    git
    gnu-netcat
    gnupg
    gptfdisk
    hddtemp
    htop
    ifplugd
    iw
    jq
    libusbmuxd
    lm_sensors
    ltrace
    macchanger
    nano
    nmap
    ntfs-3g
    openssh
    openssl
    p7zip
    polkit
    python
    python2
    ranger
    rsync
    sbsigntools
    smbclient
    sshfs
    strace
    sysstat
    tmux
    tor
    torsocks
    unrar
    unzip
    usbmuxd
    vim
    w3m
    wget
    wpa_supplicant
    inxi
    ramroot
)
# HOST1 settings:
HOST1_NAME='arch-cpu'
HOST1_SIZE='4G'
HOST1_PART=4
HOST1_PKGS=(
    "${HOST_PKGS_COMMON[@]}"
)
# HOST2 settings:
HOST2_NAME='arch-cpu-gpu'
HOST2_PART=5
HOST2_PKGS=(
    "${HOST_PKGS_COMMON[@]}"
    cuda
    opencl-amd
)
# control:
ANSWER=
HOST_NAME=
HOST_PART=
HOST_PKGS=()
# USB:
USB_MOUNT='/mnt/usb'
USB_DEVICE=
USB_INFO=
USB_SIZE_BYTES=
USB_SIZE_HUMAN=
USB_BLOCK_COUNT=
USB_BLOCK_SIZE=
# basic colors:
C_BLUE_B=$'\e[1;38;5;27m'
C_GREEN_B=$'\e[1;38;5;46m'
C_RED_B=$'\e[1;38;5;196m'
C_YELLOW_B=$'\e[1;33m'
C_WHITE_B=$'\e[1;37m'
C_GRAY=$'\e[0;37m'

##===========================  FUNCTIONS  ============================##
msg() {
# print status message:
    printf '%s==>%s %s%s\n' "$C_GREEN_B" "$C_WHITE_B" "$1" "$C_GRAY"
}

msg_ask() {
# print ask message:
    printf '%s::>%s %s%s ' "$C_BLUE_B" "$C_WHITE_B" "$1" "$C_GRAY"
}

msg_error() {
# print error message:
    printf '%s==> ERROR:%s %s%s\n' "$C_RED_B" "$C_WHITE_B" \
        "$1" "$C_GRAY"
}

msg_warn() {
# print warning message:
    printf '%s==> WARNING:%s %s%s\n' "$C_YELLOW_B" "$C_WHITE_B" \
        "$1" "$C_GRAY"
}

msg2() {
# print status sub-message:
    printf '%s ->%s %s%s\n' "$C_BLUE_B" "$C_WHITE_B" "$1" "$C_GRAY"
}

internet_status() {
# return internet connection status:
    ping -q -c1 -W3 google.com &>/dev/null || \
        ping -q -c1 -W5 archlinux.org &>/dev/null
}

usb_pacstrap() {
# pacstrap and configure basic system:
    msg "Installing $HOST_NAME Arch Linux to $USB_DEVICE$HOST_PART..."

    # pacstrap all packages:
    msg2 'pacstrap'
    pacstrap -c "$USB_MOUNT" "${HOST_PKGS[@]}"
    arch-chroot "$USB_MOUNT" paccache -rk0

    # create fstab:
    genfstab -U "$USB_MOUNT" >> "$USB_MOUNT/etc/fstab"
    sed -i "s~${USB_MOUNT}~~" "$USB_MOUNT/etc/fstab"
    msg2 'fstab created'

    # set time zone
    arch-chroot "$USB_MOUNT" ln \
        -sf "/usr/share/zoneinfo/$HOST_TIMEZONE" /etc/localtime
    msg2 "time zone set to $HOST_TIMEZONE"

    # gen /etc/adjtime:
    arch-chroot "$USB_MOUNT" hwclock --systohc

    # set language:
    sed -i "s/#${HOST_LANG}/${HOST_LANG}/" "$USB_MOUNT/etc/locale.gen"
    arch-chroot "$USB_MOUNT" locale-gen
    printf 'LANG=%s\n' "$HOST_LANG" > "$USB_MOUNT/etc/locale.conf"
    msg2 "language/locale set to $HOST_LANG"

    # set hostname:
    echo "$HOST_NAME" > "$USB_MOUNT/etc/hostname"
    echo "127.0.1.1  $HOST_NAME.localdomain  $HOST_NAME" \
        > "$USB_MOUNT/etc/hosts"
    msg2 "hostname set to $HOST_NAME"

    # set root password:
    msg2 'user root'
    if [ -n "$ROOT_PASS" ]; then
        # use ROOT_PASS as root passwd:
        printf "printf '%s\\\n%s\\\n' | passwd\n" \
            "$ROOT_PASS" "$ROOT_PASS" | arch-chroot "$USB_MOUNT"
    else
        # prompt for root passwd:
        arch-chroot "$USB_MOUNT" passwd
    fi
}

usb_config() {
# optimize system for a portable USB installation:
    # set systemd journal to use RAM:
    sed -i -e 's/#?Storage=.*/Storage=volatile/' \
        -e 's/#*SystemMaxUse=.*/SystemMaxUse=16M/' \
        "$USB_MOUNT/etc/systemd/journald.conf"
    msg2 'journaling set to use RAM'

    # disable file access time record keeping:
    sed -i 's/relatime/noatime/' "$USB_MOUNT/etc/fstab"
    msg2 'file access time record keeping disabled'

    # disable autodetect kernel hook:
    sed -i 's/^ *\(HOOKS=.*\)autodetect */\1/' \
        "$USB_MOUNT/etc/mkinitcpio.conf"
    msg2 'autodetect kernel build hook removed'

    # disable fallback initramfs image:
    sed -i "s/ *PRESETS=.*/PRESETS=('default')/" \
        "$USB_MOUNT"/etc/mkinitcpio.d/linux.preset
    rm -rf "$USB_MOUNT/boot/"*fallback*
    msg2 'fallback initrams image generation disabled'

    # enable traditional network interface naming:
    arch-chroot "$USB_MOUNT" ln -sf /dev/null \
        /etc/udev/rules.d/80-net-setup-link.rules
    msg2 'traditional network interface naming enabled'

    # disable terminal bell:
    mkdir -p "$USB_MOUNT/etc/modprobe.d"
    printf 'blacklist pcspkr\n' \
        > "$USB_MOUNT/etc/modprobe.d/nobeep.conf"
    msg2 'terminal bell disabled'

    # enable pacman color:
    sed -i 's/#*Color/Color/' "$USB_MOUNT/etc/pacman.conf"
    msg2 'pacman color enabled'
}

usb_config_grub() {
# install and configure grub on USB mounted at USB_MOUNT:
    local HOST1_MENU HOST1_UUID HOST2_MENU HOST2_UUID
    msg 'Installing and configuring grub...'

    # install grub:
    msg2 'pacstrap'
    pacstrap -c "$USB_MOUNT" grub efibootmgr
    arch-chroot "$USB_MOUNT" grub-install --target=i386-pc \
        --boot-directory /boot "$USB_DEVICE"
    arch-chroot "$USB_MOUNT" grub-install --target=x86_64-efi \
        --efi-directory /ESP --boot-directory /boot --removable

    # set menu colors and timeout:
    sed -i -e 's/#\(GRUB_COLOR_NORMAL\).*/\1="light-blue\/black"/' \
        -e 's/#\(GRUB_COLOR_HIGHLIGHT\).*/\1="light-cyan\/black"/' \
        -e 's/GRUB_TIMEOUT=.*/GRUB_TIMEOUT=2/' \
        "$USB_MOUNT/etc/default/grub"
    msg2 'grub menu colors set to light-cyan on light-blue'
    msg2 'grub menu timeout set to 2 seconds'

    # disable submenus:
    printf "\nGRUB_DISABLE_SUBMENU=y\n" >> "$USB_MOUNT/etc/default/grub"
    msg2 'grub submenus disabled'

    # create custom grub menu entries in /etc/grub.d/40_custom:
    arch-chroot "$USB_MOUNT" grub-mkconfig -o /boot/grub/grub.cfg
    HOST1_UUID=$(lsblk -f | \
        grep -Po "${USB_DEVICE##*/}${HOST1_PART}\s+ext4\s+\K[^\s]+")
    HOST2_UUID=$(lsblk -f | \
        grep -Po "${USB_DEVICE##*/}${HOST2_PART}\s+ext4\s+\K[^\s]+")
    HOST1_MENU="$(sed -n "/^menuentry 'Arch/,/^}/p" \
        "$USB_MOUNT/boot/grub/grub.cfg" | \
        sed "s/, with Linux linux/ (${HOST1_NAME})/g")"
    HOST2_MENU="$(sed -e "s/${HOST1_UUID}/${HOST2_UUID}/g" \
        -e "s/${HOST1_NAME}/${HOST2_NAME}/g" <<<"$HOST1_MENU")"
    { printf '%s\n\n%s\n\n' "$HOST1_MENU" "$HOST2_MENU"
    printf 'if [ %s == "efi" ]; then\n' "\${grub_platform}"
    printf '    menuentry "Firmware Setup" {\n'
    printf '        fwsetup\n    }\nfi\n\n'
    printf 'menuentry "Shutdown" {\n    halt\n}\n'
        } >> "$USB_MOUNT/etc/grub.d/40_custom"
    msg2 'custom grub menu entries created in /etc/grub.d/40_custom'

    # disable automatic grub menu entry generation for linux partitions:
    arch-chroot "$USB_MOUNT" chmod -x /etc/grub.d/10_linux
    msg2 'automatic menu entry generation for linux partitions disabled'

    # generate grub config:
    arch-chroot "$USB_MOUNT" grub-mkconfig -o /boot/grub/grub.cfg
}

usb_config_shim_signed() {
# install and enable shim-signed boot loader:
    msg 'Installing and enabling shim-signed...'
    msg2 'pacstrap'
    pacstrap -c "$USB_MOUNT" shim-signed
    mv "$USB_MOUNT/ESP/EFI/BOOT/BOOTX64.efi" \
        "$USB_MOUNT/ESP/EFI/BOOT/grubx64.efi"
    cp "$USB_MOUNT/usr/share/shim-signed/shimx64.efi" \
        "$USB_MOUNT/ESP/EFI/BOOT/BOOTX64.efi"
    cp "$USB_MOUNT/usr/share/shim-signed/mmx64.efi" \
        "$USB_MOUNT/ESP/EFI/BOOT/mmx64.efi"
}

usb_config_large_memory_pages_enable() {
# enable large memory pages:
    sed -i 's/# End of file//' "$USB_MOUNT/etc/security/limits.conf"
    { printf '*  soft  memlock  262144\n*  hard  memlock  262144\n'
    printf '# End of file\n'
        } >> "$USB_MOUNT/etc/security/limits.conf"
    mkdir -p "$USB_MOUNT/etc/sysctl.d"
    printf 'vm.nr_hugepages=128\n' \
        > "$USB_MOUNT/etc/sysctl.d/99-sysctl.conf"
    msg2 'large memory pages enabled'
}

usb_config_sudo_lecture_disable() {
# disable sudo lecture message:
    printf 'Defaults lecture = never\n' \
        > "$USB_MOUNT/etc/sudoers.d/01-neverlecture"
}

usb_config_autologin_enable() {
# enable autologin for USER_NAME on tty1:
    local SYSTEM_DIR="$USB_MOUNT/etc/systemd/system"
    mkdir -p "$SYSTEM_DIR/getty@tty1.service.d"
    { printf '[Service]\nExecStart=\nExecStart=/usr/bin/agetty --auto'
    printf 'login %s --noclear %s %s\n' "$USER_NAME" '%I' "\$TERM"
        } >> "$SYSTEM_DIR/getty@tty1.service.d/override.conf"
}

usb_config_capslock_to_escape() {
# map Caps_Lock key to Escape key:
    gunzip -c "$HOST_KEYMAP" | sed 's/Caps_Lock/Escape/' \
        > "$USB_MOUNT/etc/vconsole.map"
    printf 'KEYMAP=/etc/vconsole.map\n' > "$USB_MOUNT/etc/vconsole.conf"
}

usb_issue_copy() {
# copy custom /etc/issue:
    if [ -f "$SCRIPT_DIR/.root/etc/issue_$HOST_NAME" ]; then
        cp "$SCRIPT_DIR/.root/etc/issue_$HOST_NAME" \
            "$USB_MOUNT/etc/issue"
        msg2 'custom /etc/issue copied'
    elif [ -f "$SCRIPT_DIR/.root/etc/issue" ]; then
        cp "$SCRIPT_DIR/.root/etc/issue" "$USB_MOUNT/etc/issue"
        msg2 'custom /etc/issue copied'
    fi
}

usb_root_copy() {
# copy root home folder:
    if [ -d "$SCRIPT_DIR/.root/root/" ]; then
        rsync -a "$SCRIPT_DIR/.root/root/" "$USB_MOUNT/root/"
        msg2 "root home folded copied from $SCRIPT_DIR/.root/root/"
    fi
}

usb_user_add() {
# add USER_NAME and configure sudo NOPASSWD commands:
    msg2 "useradd $USER_NAME"
    arch-chroot "$USB_MOUNT" useradd -m "$USER_NAME" &>/dev/null
    if [ -n "$USER_PASS" ]; then
        printf "printf '%s\\\n%s\\\n' | passwd %s\n" \
            "$USER_PASS" "$USER_PASS" "$USER_NAME" | \
            arch-chroot "$USB_MOUNT"
    else
        arch-chroot "$USB_MOUNT" passwd "$USER_NAME"
    fi

    # configure sudo user commands:
    mkdir -p "$USB_MOUNT/etc/sudoers.d"
    { printf '%s ALL=(ALL) ALL\n' "$USER_NAME"
    if [ -n "${USER_COMMANDS_NOPASS[0]}" ]; then
        printf '%s ALL=(ALL) NOPASSWD: ' "$USER_NAME"
        printf '%s' "${USER_COMMANDS_NOPASS[0]}"
        for CMD in "${USER_COMMANDS_NOPASS[@]:1}"; do
            printf ', %s' "$CMD"
        done
        printf '\n'
    fi ;} > "$USB_MOUNT/etc/sudoers.d/10-$USER_NAME"
    msg2 "$USER_NAME sudo access configured"
}

usb_user_copy() {
# copy USER_NAME home folder:
    if [ -d "$SCRIPT_DIR/$USER_NAME/" ]; then
        rsync -a "$SCRIPT_DIR/$USER_NAME/" "$USB_MOUNT/home/$USER_NAME"
        arch-chroot "$USB_MOUNT" chown -R \
            "$USER_NAME:$USER_NAME" "/home/$USER_NAME"
        msg2 "$USER_NAME files copied from $SCRIPT_DIR/$USER_NAME/"
    elif [ -d "$SCRIPT_DIR/user/" ]; then
        rsync -a "$SCRIPT_DIR/user/" "$USB_MOUNT/home/$USER_NAME"
        arch-chroot "$USB_MOUNT" chown -R \
            "$USER_NAME:$USER_NAME" "/home/$USER_NAME"
        msg2 "$USER_NAME files copied from $SCRIPT_DIR/user/"
    fi
}

usb_user_repo_add() {
# add local user repo to pacman.conf:
    if [ -d "$USB_MOUNT/home/$USER_NAME/repo" ]; then
        { printf '[%s-repo]\nSigLevel = Optional\n' "$USER_NAME"
        printf 'Server = file:///home/%s/repo\n' "$USER_NAME"
            } >> "$USB_MOUNT/etc/pacman.conf"
        arch-chroot "$USB_MOUNT" pacman -Sy
        msg2 "/home/$USER_NAME/repo added to /etc/pacman.conf"
    fi
}

usb_reboot_script_make() {
# create post reboot script:
    cat <<'REBOOT_SCRIPT' > "$USB_MOUNT/root/post-reboot.sh"
#!/bin/bash
C_BLUE_B=$'\e[1;38;5;27m'
C_GREEN_B=$'\e[1;38;5;46m'
C_RED_B=$'\e[1;38;5;196m'
C_YELLOW_B=$'\e[1;33m'
C_WHITE_B=$'\e[1;37m'
C_GRAY=$'\e[0;37m'
msg() {
    printf '%s==>%s %s%s\n' "$C_GREEN_B" "$C_WHITE_B" "$1" "$C_GRAY"
}
msg_error() {
    printf '%s==> ERROR:%s %s%s\n' "$C_RED_B" "$C_WHITE_B" \
        "$1" "$C_GRAY"
}
msg_warn() {
    printf '%s==> WARNING:%s %s%s\n' "$C_YELLOW_B" "$C_WHITE_B" \
        "$1" "$C_GRAY"
}

# setup ifplugd for automatic ethernet configuration:
if (ip link | grep 'eth0:' &>/dev/null); then
    cp /etc/netctl/examples/ethernet-dhcp "/etc/netctl/eth0-$HOSTNAME"
    systemctl start netctl-ifplugd@eth0.service
    systemctl enable netctl-ifplugd@eth0.service
    msg 'automatic ethernet configuration enabled'
else
    msg_warn 'eth0 not found: automatic ethernet configuration disabled'
fi

# start network time protocol:
timedatectl set-ntp true
msg 'network time sync enabled'

# configure sshd.socket service:
mkdir -p /etc/systemd/system/sshd.socket.d/
printf '[Socket]\nListenStream=\nListenStream=22322\n' \
    > /etc/systemd/system/sshd.socket.d/override.conf
printf 'Port 22322\nAllowUsers bot\nPermitRootLogin no\n' \
    >> /etc/ssh/sshd_config
systemctl start sshd.socket
systemctl enable sshd.socket
msg 'ssh server enabled on port 22322'

# enable tor:
systemctl start tor.service
systemctl enable tor.service
msg 'tor service enabled'
REBOOT_SCRIPT
    chmod +x "$USB_MOUNT/root/post-reboot.sh"
    msg_warn 'execute /root/post-reboot.sh after reboot'
}

usb_mount() {
# set $1=HOST_NAME; set HOST_PART, HOST_PKGS; mount HOST_NAME:
    if [ "$1" = "$HOST1_NAME" ]; then
        HOST_NAME="$HOST1_NAME"
        HOST_PART="$HOST1_PART"
        HOST_PKGS=("${HOST1_PKGS[@]}")
    elif [ "$1" = "$HOST2_NAME" ]; then
        HOST_NAME="$HOST2_NAME"
        HOST_PART="$HOST2_PART"
        HOST_PKGS=("${HOST2_PKGS[@]}")
    elif [ -n "$1" ]; then
        msg_error "hostname $1 in usb_mount() not found"
        exit 3
    else
        msg_error 'no hostname supplied to usb_mount()'
        exit 3
    fi
    # mount root:
    mkdir -p "$USB_MOUNT"
    mount "${USB_DEVICE}$HOST_PART" "$USB_MOUNT"
    # mount ESP:
    mkdir -p "$USB_MOUNT/ESP"
    mount "${USB_DEVICE}2" "$USB_MOUNT/ESP"
    # mount home:
    mkdir -p "$USB_MOUNT/home"
    mount "${USB_DEVICE}3" "$USB_MOUNT/home"
    # bind-mount boot:
    mkdir -p "$USB_MOUNT/boot"
    mkdir -p "$USB_MOUNT/ESP/$HOST_NAME"
    mount --bind "$USB_MOUNT/ESP/$HOST_NAME" "$USB_MOUNT/boot"
    msg "${USB_DEVICE}$HOST_PART ${USB_DEVICE}2 ${USB_DEVICE}3 mounted"
}

usb_umount() {
# umount USB partitions:
    local FLAG_UMOUNT='false'
    if (mountpoint "$USB_MOUNT" &>/dev/null); then
        printf '%s==>%s umount%s' "$C_GREEN_B" "$C_WHITE_B" "$C_GRAY"
        FLAG_UMOUNT='true'
    fi
    # umount boot:
    if (mountpoint "$USB_MOUNT/boot" &>/dev/null); then
        umount "$USB_MOUNT/boot"
        printf '%s %s/boot%s' "$C_WHITE_B" "$USB_MOUNT" "$C_GRAY"
    fi
    # umount ESP:
    if (mountpoint "$USB_MOUNT/ESP" &>/dev/null); then
        umount "$USB_MOUNT/ESP"
        printf '%s %s/ESP%s' "$C_WHITE_B" "$USB_MOUNT" "$C_GRAY"
    fi
    # umount home:
    if (mountpoint "$USB_MOUNT/home" &>/dev/null); then
        umount "$USB_MOUNT/home"
        printf '%s %s/home%s' "$C_WHITE_B" "$USB_MOUNT" "$C_GRAY"
    fi
    # umount root:
    if (mountpoint "$USB_MOUNT" &>/dev/null); then
        umount "$USB_MOUNT"
        printf '%s %s%s' "$C_WHITE_B" "$USB_MOUNT" "$C_GRAY"
    fi
    if [ "$FLAG_UMOUNT" = 'true' ]; then
        printf '\n'
    fi
}

usb_sync() {
# sync USB memory:
    msg "syncing $USB_DEVICE..."
    sync
}

mk-usb_kill() {
# kill trap:
    usb_umount
    exit 3
}

##=============================  SCRIPT  =============================##
# exit on error:
set -e

# FAIL: must be run as root:
if [ "$EUID" -ne 0 ]; then
    msg_error 'must be run as root'
    exit 2
fi

# verify packages and settings:
msg 'Verifying packages and settings...'
USB_DEVICE="$1"

# FAIL: no argument given:
if [ -z "$USB_DEVICE" ]; then
    msg_error 'no argument given'
    exit 1
# FAIL: argument not a device:
elif ! [[ "$USB_DEVICE" =~ ^/dev/sd[a-z]$ ]]; then
    msg_error "not a device: $USB_DEVICE"
    exit 1
fi

# FAIL: invalid hostname HOST1_NAME:
if ! [[ "$HOST1_NAME" =~ ^[a-z0-9\-]+$ ]]; then
    msg_error "invalid hostname: $HOST1_NAME"
    exit 1
fi

# FAIL: invalid hostname HOST2_NAME:
if ! [[ "$HOST2_NAME" =~ ^[a-z0-9\-]+$ ]]; then
    msg_error "invalid hostname: $HOST2_NAME"
    exit 1
fi

# FAIL: hostnames not unique:
if [ "$HOST1_NAME" = "$HOST2_NAME" ]; then
    msg_error "non-unique hostnames"
    exit 1
fi

# FAIL: invalid language HOST_LANG:
if ! (grep -P "^\s?#?\s?$HOST_LANG" /etc/locale.gen &>/dev/null); then
    msg_error "invalid language: $HOST_LANG"
    exit 1
fi

# FAIL: invalid time zone HOST_TIMEZONE:
if ! [ -f "/usr/share/zoneinfo/$HOST_TIMEZONE" ]; then
    msg_error "invalid time zone: $HOST_TIMEZONE"
    exit 1
fi

# FAIL: invalid username USER_NAME:
if ! [[ "$USER_NAME" =~ ^[A-Za-z0-9\-]+$ ]]; then
    msg_error "invalid username: $USER_NAME"
    exit 1
fi

# FAIL: keymap not valid:
if [ -n "$HOST_KEYMAP" ] && [ ! -f "$HOST_KEYMAP" ]; then
    msg_error "invalid keymap: $HOST_KEYMAP"
elif [ -z "$HOST_KEYMAP" ]; then
    HOST_KEYMAP='/usr/share/kbd/keymaps/i386/qwerty/us.map.gz'
fi

# FAIL: device mounted:
if (grep "$USB_DEVICE" /proc/mounts &>/dev/null); then
    msg_error "already mounted: $USB_DEVICE"
    exit 1
fi

# FAIL: no internet connection:
if ! (internet_status); then
    msg_error 'no internet connection'
    exit 1
fi

# FAIL: mount point not clear:
if (mountpoint "$USB_MOUNT" &>/dev/null) || \
{ [ -d "$USB_MOUNT" ] && [ -n "$(ls -A "$USB_MOUNT")" ]; }; then
    msg_error "$USB_MOUNT not clear"
    exit 1
fi

# get USB device info:
USB_INFO="$(fdisk --color=never -l "$USB_DEVICE")"
USB_SIZE_BYTES="$(grep -Po "$USB_DEVICE:.+ \K[0-9]+(?= bytes)" \
    <<< "$USB_INFO")"
USB_SIZE_HUMAN="$(grep -Po "$USB_DEVICE: *\K[^,]+" <<< "$USB_INFO")"
USB_BLOCK_SIZE="$(grep -Po "Sector size.* \K[0-9]+" <<< "$USB_INFO")"
USB_BLOCK_COUNT=$((USB_SIZE_BYTES / USB_BLOCK_SIZE))

# FAIL: USB not big enough:
if [ "$USB_SIZE_BYTES" -lt 15560000000 ]; then
    msg_error 'USB must be at least 14.5G'
    exit 1
fi

# FAIL: package not found:
for PKG in $(printf '%s\n%s\n' "${HOST1_PKGS[@]}" "${HOST2_PKGS[@]}" | \
sort -u); do if ! (pacman -Si "$PKG" &>/dev/null) && \
! (pacman -Sg "$PKG" &>/dev/null); then
    msg_error "package not found: $PKG"
    exit 1
fi; done

# warn: all data will be lost:
msg_warn "All data on $USB_DEVICE ($USB_SIZE_HUMAN) will be lost."
msg_ask 'Proceed with installation? [Y/n]'
read -r ANSWER
if [[ "${ANSWER,,}" =~ ^(n|no)$ ]]; then
    exit 0
fi

# zero out USB:
msg_ask 'Zero out USB? [Y/n]'
read -r ANSWER
if ! [[ "${ANSWER,,}" =~ ^(n|no)$ ]]; then
    dd status=progress if=/dev/zero of="$USB_DEVICE" \
        bs="$USB_BLOCK_SIZE" count="$USB_BLOCK_COUNT"
fi

# partition USB:
msg 'Partitioning USB...'
sgdisk -o \
    -n 1:0:+10M -t 1:EF02 \
    -n 2:0:+500M -t 2:EF00 \
    -n "3:0:+$HOME_SIZE" -t 3:8300 \
    -n "${HOST1_PART}:0:+$HOST1_SIZE" -t 3:8300 \
    -n "${HOST2_PART}:0:-5M" -t 4:8300 \
    "$USB_DEVICE"

# format partitions:
msg 'Formatting partitions...'
mkfs.fat -F32 "${USB_DEVICE}2"
mkfs.ext4 -F "${USB_DEVICE}3"
mkfs.ext4 -F "${USB_DEVICE}4"
mkfs.ext4 -F "${USB_DEVICE}5"

# set kill umount trap:
trap mk-usb_kill ABRT EXIT HUP ILL INT QUIT SYS TERM

# HOST2:
usb_mount "$HOST2_NAME"
usb_pacstrap
usb_config
usb_config_capslock_to_escape
usb_config_large_memory_pages_enable
usb_config_autologin_enable
usb_config_sudo_lecture_disable
usb_issue_copy
usb_root_copy
usb_user_add
usb_user_copy
usb_user_repo_add
usb_reboot_script_make
usb_umount
usb_sync

# HOST1: installed second to handle grub configuration:
usb_mount "$HOST1_NAME"
usb_pacstrap
usb_config
usb_config_grub
usb_config_shim_signed
usb_config_capslock_to_escape
usb_config_large_memory_pages_enable
usb_config_autologin_enable
usb_config_sudo_lecture_disable
usb_issue_copy
usb_root_copy
usb_user_add
usb_user_repo_add
usb_reboot_script_make
usb_umount
usb_sync

msg "$USB_DEVICE Arch Linux install complete"
exit 0