Ubuntu Impish (21.10) Raspberry Pi4B distribution check and 'linux-modules-extra-raspi' "auto-installer" (fingers crossed!)

ubuntu-rpi-linuxmodules.sh

#!/bin/bash
# this script will download and install the 'linux-modules-extra-raspi' package if:
#
# 1. the Linux distribution is detected as Ubuntu, and
# 2. the mentioned package is not installed on the system according to dpkg.
#
# The packages are:
# On the Raspberry Pi: apt package 'linux-modules-extra[-raspi]', or:
# on x86_64 (amd64) environments, named according to the kernel that's in use.
# is required starting from Ubuntu Impish to install zram-swap
#
# For more info on the purpose of this script, please see:
# https://github.com/foundObjects/zram-swap (I'm not affiliated with the project.)
# or, more specifically: https://github.com/foundObjects/zram-swap/issues/8

# First, we check if we're running Ubuntu.
if [  -n "$(uname -a | grep Ubuntu)" ]; then
echo "INFO: Your distribution was detected as Ubuntu." &&
echo "INFO: This might require extra apt packages to be installed."

# get the kernel version to be used for suffixes on generic packages
  kernelver=$(uname -r)
  export kernelver

# check for aarch64 (Raspberry Pi, etc.)
checkcpu="aarch64"
export checkcpu

  if [ $(uname -p | grep -c "$checkcpu") -eq 1 ];
  then
  echo "INFO: Detected your processor as $checkcpu."
  
  raspicheck=$(cat /proc/device-tree/model | grep -c "Raspberry Pi")
  export raspicheck
  
    if [ $raspicheck -eq 1 ]; 
    then
  	aptrequired="linux-modules-extra-raspi"
	export aptrequired    
	echo "INFO: Your computer was detected as Raspberry Pi."
        echo "INFO: Will be requiring $aptrequired to be installed."	

    else    
        aptrequired="linux-modules-extra-$kernelver"
	export aptrequired
    	echo "INFO: You will (likely) need the generic $aptrequired for your kernel."
    	echo "INFO: This is however completely untested on other aarch64 platforms than the RPi4B as for this script." 
    fi  
  fi

# check for x86_64
checkcpu="x86_64"
export checkcpu

  if [ $(uname -p | grep -c "$checkcpu") -eq 1 ];
  then
  echo "INFO: Detected your processor as $checkcpu."
  aptrequired="linux-modules-extra-$kernelver"
  export aptrequired
  
  echo "INFO: Will be requiring $aptrequired to be installed."
  fi

# Look for the required apt package.
  if [ $(dpkg-query -W -f='${Status}' $aptrequired 2>/dev/null | grep -c "ok installed") -eq 0 ];
  then
# Install it if it's not found.
  echo "INFO: Package $aptrequired not installed!" &&
  echo "INFO: Getting it via apt-get now." &&
  echo "Running apt-get update & upgrade first..."
  sudo apt-get update &&
  sudo apt-get upgrade &&
  echo "Installing the $aptrequired package via apt-get..."
  sudo apt-get install $aptrequired &&

# Double-checking that the package IS indeed installed! Rather be safe than sorry! :o)
  echo "Making sure the package is now installed."
  if [ $(dpkg-query -W -f='${Status}' $aptrequired 2>/dev/null | grep -c "ok installed") -eq 0 ];
  then
  echo "ERROR! Package wasn't installed successfully!"
  echo "ERROR! Please either re-run the installer or try reconfiguring/fixing your dpkg/apt-get so that $aptrequired is properly installed on this system."
  exit 1
  fi
  else
  echo "INFO: The required apt package $aptrequired is installed."
  fi    
  echo "OK!"
fi

Feel free to comment if this needs improvements or doesn't work out for you! Thanks!