LM_iso_verify.sh

#!/bin/bash

# Save this file in the ~/bin folder (or other convenient locations) as LM_iso_verify.sh
# When you want to check the integrity of the downloaded LMxx.x .iso file:
#
# Download or move your Mint xx.x.iso file to your Downloads folder.
# Move this LM_iso_verify.sh file to the Downloads folder
#  and make sure it is marked as executable.  (Or if you keep it in /home/<your user name>/bin,
#  then it is should already be on the PATH, and you don't need to move it.)
#
# Open a terminal window and cd to ~/Downloads, then
# run the script with "./LM_iso_verify.sh  Mint-xx.x-correct-filename.iso"
# EXAMPLE:   ./LM_iso_verify.sh  linuxmint-18.3-cinnamon-64bit.iso
# or if the script is in /home/bin or otherwise on the PATH, then
# EXAMPLE:     LM_iso_verify.sh  linuxmint-18.3-cinnamon-64bit.iso



# Check for one parameter on the command line (the .iso file name)
if [ $# -ne 1 ]; then
	echo "Usage: $(basename "$0") linuxmint-xx.x-correct-filename.iso"
	exit 1
fi

# Check if that file exists in the working directory and is readable
if [ ! -r "$1" ]; then
	echo "File $1 does not exist or is not readable"
	exit 1
fi

# Importing the signing key (LM18 and higher)
gpg --keyserver keyserver.ubuntu.com --recv-key "27DE B156 44C6 B3CF 3BD7 D291 300F 846B A25B AE09"



# This is for LM18.3 versions - modify these wget lines as needed for other versions
# Download the Mint 18.3 sha256 sum txt files

# If heanet.ie site isn't working, comment out these two lines and uncomment the wget lines for the alternate site
#    or use another alternate of your choice.
wget https://ftp.heanet.ie/mirrors/linuxmint.com/stable/18.3/sha256sum.txt
wget https://ftp.heanet.ie/mirrors/linuxmint.com/stable/18.3/sha256sum.txt.gpg

# University of Oklahoma mirror - an alternate site if above heanet.ie isn't working
#wget http://reflection.oss.ou.edu/linuxmint/isos/linuxmint.com/stable/18.3/sha256sum.txt
#wget http://reflection.oss.ou.edu/linuxmint/isos/linuxmint.com/stable/18.3/sha256sum.txt.gpg




# Verify the signature on the sha256 sum text file
gpg --verify sha256sum.txt.gpg sha256sum.txt
echo "It should report that the signature is Good, $USER."
echo "You can ignore any warning about ...not certified..."
echo "..."

# compare the sha256 sum of your ISO image and the original Mint sha256 sum
echo "Calculating the sha256 sum for $1 and comparing it to the downloaded signed sha256 sum"
echo "Be patient, $USER. I am not that good at math"
echo "..."

sha256sum --check --ignore-missing sha256sum.txt


echo "Done."