How to use md5sum check {SOLVED}

AndyInMokum · 07-21-2013, 05:34 AM

Greetings from Amsterdam

I'm having problems with md5sum check. I cannot get it to work. I download a iso file and save it. I then open a terminal and type:

md5sum "space"

I go to the saved ISO file and right click and go to properties. I then copy the file name and past it into the terminal.

andy1960@debimint-li-3710 ~ $ md5sum linuxmint-15-cinnamon-dvd-32bit.iso
md5sum: linuxmint-15-cinnamon-dvd-32bit.iso: No such file or directory
andy1960@debimint-li-3710 ~ $

Tried it as root, the result was the same.

Where and what am I doing wrong? Many thanks.

druuna · 07-21-2013, 06:09 AM

When you open a terminal your current directory is your home directory (/home/username). Your downloaded iso file is stored at a different location.

Assuming you have downloaded it to /home/username/Downloads, you need to do the following (as normal user, from a terminal):

Code:

cd Downloads
md5sum linuxmint-15-cinnamon-dvd-32bit.iso

This would also work (no cd needed):

Code:

md5sum Downloads/linuxmint-15-cinnamon-dvd-32bit.iso

AndyInMokum · 07-21-2013, 06:26 AM

Quote:

Originally Posted by druuna

When you open a terminal your current directory is your home directory (/home/username). Your downloaded iso file is stored at a different location.

Assuming you have downloaded it to /home/username/Downloads, you need to do the following (as normal user, from a terminal):

Code:

cd Downloads
md5sum linuxmint-15-cinnamon-dvd-32bit.iso

This would also work (no cd needed):

Code:

md5sum Downloads/linuxmint-15-cinnamon-dvd-32bit.iso

Hi druuna

Many thanks, that's done the trick. The file was on my Desktop. I just forgot to change the directory. Now I can enjoy the sun in Westerpark. Thanks again.

druuna · 07-21-2013, 06:53 AM

You're welcome

BTW: There's a click-able link on the top right-hand side that puts up the [SOLVED] tag, no need to do this by hand

David the H. · 07-21-2013, 11:23 AM

A few years ago during a bout of serious scriptwriting practice I created one that makes comparing checksums easier. Perhaps it will be of help to you.

I named it "comparisum", but you can call it whatever you want. Copy it to a file, chmod it to be executable, and run the -h option for a full description of how to use it.

Code:

#!/bin/bash

checktype="sha1sum"	#Sets the default checksum used for file comparisons.
			#string is the name of the command you want it to use:
			#md5sum,sha1sum,sha224sum,sha256sum,sha384sum,sha512sum

EX_HELPOUT=79		#User-defined exit.  Successful output of usage information.
EX_USAGE=64		#Standard C exit code for bad arguments.  See /usr/include/sysexits.h
EX_RESULT=		#Used for the valid comparison result exit code.  Will be either 0 or 1

IFS=$'\n'		#Set IFS to newline, to deal with names with spaces
			#(Not really necessary, but it doesn't hurt)

BCYAN="${BCYAN:-\e[1;36m}"	#Define some color codes, for prettified output.
BGREEN="${BGREEN:-\e[1;32m}"	#Use environment defaults if they exist.
BRED="${BRED:-\e[1;31m}"
BBLUE="${BBLUE:-\e[1;34m}"
BMAGENTA="${BMAGENTA:-\e[1;35m}"
RESET="${RESET:-\e[0m}"


## function that outputs usage info ##
ShowHelp() {

	local -a help

	#Use array indexes 0-4 for short help.
	help+=( ""																		)
	help+=( "\tUsage:  ${BCYAN}${0##*/} [-t <type>] <file1|checksum1> <file2|checksum2>${RESET}"		)
	help+=( ""																		)
	help+=( "\t\t${BCYAN}${0##*/} -h${RESET} for detailed help"									)
	help+=( ""																		)
	#Use array indexes 5+ for long help.
	help+=( ""																		)
	help+=( "\tUsage:\t${BCYAN}${0##*/} [-t <type>] <file1|checksum1> <file2|checksum2>${RESET}"		)
	help+=( "\t\t${BCYAN}${0##*/} -h${RESET}"												)
	help+=( ""																		)
	help+=( "\t${BBLUE}-h${RESET}\t\t: Display this help message and exit."						)
	help+=( ""																		)
	help+=( "\t${BBLUE}-t <type>${RESET}\t: Use checksum <type> instead of the default."				)
	help+=( "\t\t\t: Valid types are: md5 sha1 sha224 sha256 sha384 sha512"						)
	help+=( ""																		)
	help+=( "\tThis script will compare the sha1, sha2, or md5 checksums of two files,"				)
	help+=( "\tone file and a previously-generated checksum, or two checksums."					)
	help+=( ""																		)
	help+=( "\tIf two filenames are given it will calculate and compare their checksums."			)
	help+=( "\tIt uses sha1 by default.  This can be changed in the script, or you can"				)
	help+=( "\tspecify a different checksum type with the '-t' option.  If multiple types"			)
	help+=( "\tare given, only the last one will be used."										)
	help+=( ""																		)
	help+=( "\tThe '-t' option is ignored when comparing a file to an entered checksum."				)
	help+=( "\tThe script will automatically determine the checksum type based on the"				)
	help+=( "\tlength of the string supplied to it."											)
	help+=( ""																		)
	help+=( "\tIf neither argument is a valid file, then it will compare them as"					)
	help+=( "\tliteral text strings.  This may be useful for comparing long checksums."				)
	help+=( "\tIn this case the strings can have any length or content."							)
	help+=( ""																		)
	help+=( "\tThe exit code will be 0 if the entries match, and 1 if they don't."					)
	help+=( "\t( In addition, 64 = improper arguments and 79 = this help option. )"					)
	help+=( ""																		)

	if [[ "$1" == "short" ]]; then
		echo -e "${help[*]:0:5}"
	elif [[ "$1" == "long" ]]; then
		echo -e "${help[*]:5}"
	fi
}


## function that calculates checksums for files ##
Check_Sum() {

	sum1=$( "$checktype" "$1" )
	echo "${sum1%% *}"

}


## function that compares the checksums of two files ##
Compare2Files() {

	# run both files through the Check_Sum function
	filesum1=$( Check_Sum "$1" )
	filesum2=$( Check_Sum "$2" )

	# compare and display the results
	filename1="${1##*/}"  #strip leading directories
	filename2="${2##*/}"  # for display purposes

	echo
	echo -e "Comparing files ${BCYAN}$filename1${RESET} and ${BCYAN}$filename2${RESET}."
	echo -e "Using ${BCYAN}$checktype${RESET} for comparison."
	echo
	echo -e "Sum of $filename1 is:\n${BBLUE}$filesum1${RESET}"
	echo -e "Sum of $filename2 is:\n${BBLUE}$filesum2${RESET}"
	echo
	if [[ "$filesum1" == "$filesum2" ]]; then
		echo -e "${BGREEN}The two files match.${RESET}"
		EX_RESULT=0
	else
		echo -e "${BRED}The two files are different.${RESET}"
		EX_RESULT=1
	fi
}


## function that compares a file checksum to a given string ##
CompareFile2Sum() {

	if [[ -f "$1" ]]; then	#determine the order of arguments
		file="$1"
		filename="${1##*/}"
		compstring="$2"
	else
		file="$2"
		filename="${2##*/}"
		compstring="$1"
	fi

	#Determine if $compstring is a valid checksum, and which type it is.
	#First reject non-hex strings, then test for length.

	if [[ "$compstring" =~ [^[:xdigit:]] ]]; then
		echo
		echo -e "${BMAGENTA}String to compare is not a valid checksum.  Exiting.${RESET}" >&2
		ShowHelp short >&2
		exit "$EX_USAGE"
	fi

	case "${#compstring}" in
		32) checktype=md5sum ;;
		40) checktype=sha1sum ;;
		56) checktype=sha224sum ;;
		64) checktype=sha256sum ;;
		96) checktype=sha384sum ;;
		128) checktype=sha512sum ;;
		*) 	echo
			echo -e "${BMAGENTA}String to compare is not a valid checksum.  Exiting.${RESET}" >&2
			ShowHelp short >&2
			exit "$EX_USAGE" ;;
	esac

	filesum=$( Check_Sum "$file" )

	echo
	echo -e "Comparing ${BCYAN}$filename${RESET} to the checksum given."
	echo -e "Using ${BCYAN}$checktype${RESET} for comparison."
	echo
	echo -e "Sum of $filename is:\n${BBLUE}$filesum${RESET}"
	echo -e "Sum to compare against is:\n${BBLUE}$compstring${RESET}"
	echo
	if [[ "$filesum" == "$compstring" ]]; then
		echo -e "${BGREEN}The two checksums match.${RESET}"
		EX_RESULT=0
	else
		echo -e "${BRED}The two checksums are different.${RESET}"
		EX_RESULT=1
	fi

}

## function that compares two strings ##
Compare2Strings() {

	echo
	echo "Comparing text string one to text string two."
	echo
	echo -e "Text string one is:\n${BBLUE}$1${RESET}"
	echo -e "Text string two is:\n${BBLUE}$2${RESET}"
	echo
	if [[ "$1" == "$2" ]]; then
		echo -e "${BGREEN}The two text strings match.${RESET}"
		EX_RESULT=0
	else
		echo -e "${BRED}The two text strings are different.${RESET}"
		EX_RESULT=1
	fi

}


###### Start main script operations ######
##########################################

## Process input options ##
while getopts ":ht:" opt; do
	case "$opt" in
		h) ShowHelp long >&2
		   exit "$EX_HELPOUT"
		;;
		t) case "$OPTARG" in
			md5|sha1|sha224|sha256|sha384|sha512) checktype="${OPTARG}sum"
			;;
			*) echo
			   echo -e "${BMAGENTA}Invalid type \"${BRED}$OPTARG${BMAGENTA}\".${RESET}" >&2
			   echo -e "${BMAGENTA}Valid types are ${BRED}md5 sha1 sha224 sha256 sha384 sha512${RESET}" >&2
			   ShowHelp short >&2
			   exit "$EX_USAGE"
			;;
		   esac
		;;
		\?) echo -e "${BMAGENTA}Invalid option \"${BRED}-$OPTARG${BMAGENTA}\".  Ignoring.${RESET}" >&2
		;;
	esac
done

shift $(( OPTIND - 1 )) ; OPTIND=1


## Analyze input arguments (after shifting away options) and call the appropriate functions ##

if [[ ! "$2" || "$3" ]]; then				#must have exactly two arguments.

	echo
	echo -e "${BMAGENTA}Invalid number of arguments.${RESET}" >&2
	ShowHelp short >&2
	exit "$EX_USAGE"

elif [[ -f  "$1" && -f "$2" ]]; then		# If both are files...

	Compare2Files "$1" "$2"

elif [[ ! -f  "$1" && ! -f "$2" ]]; then	# If neither are files...

	Compare2Strings "$1" "$2"

elif [[ ! -f "$1" || ! -f "$2" ]]; then		# If only one is a file...

	CompareFile2Sum "$1" "$2"

fi

echo

exit "$EX_RESULT"