Md5 hash generator linux

How to get the MD5 hash of a string directly in the terminal?

How do I get the MD5 hash of a string directly from the terminal? For example, I want the string abcdefg hashed. Currently the md5sum command only accepts a filename as input. I want to simply enter the following line and everything be done with.

md5sum abcdefg output: ac54bcf346e578feb46888b3ecd2344f 

9 Answers 9

You can also say something like this :

~$ echo -n Welcome | md5sum 83218ac34c1834c26781fe4bde918ee4 - 

It basically does the same thing as described by @enzotib, but is perhaps a bit simpler.

You also want to update the example result, as 7803ffca. is the result with the added newline. The correct result for the command above is 83218ac34c1834c26781fe4bde918ee4 —

Please correct me if I’m wrong, but I think this is because the MD5sum was applied to a stream of data, as opposed to reading a file content, which has a name associated to it.

Notice that the -n is mandatory. Without it, your hash will be totally wrong since it includes the newline character.

@alper echo -n Welcome | md5sum | awk ‘‘ will take the first «column» separated by spaces. You could also use cut as well.

Very simple, it accepts stdin, so

To avoid the trailing newline added by the shell:

printf '%s' "my string" | md5sum 

+1 for using printf correctly. If you want to have the sum without the — , put | cut -d ‘ ‘ -f 1 . Example usage: sum=$(printf ‘%s’ ‘some string’ | md5sum | cut -d ‘ ‘ -f 1)

it’s weird but the

I got wrong result with the first command b9bfa87a6a126911f2246c7a615bff27 — instead of 2ba81a47c5512d9e23c435c1f29373cb —

$ echo -n 123456 | md5sum | awk '' e10adc3949ba59abbe56e057f20f883e 

you can create a shell script.

For example,the script name is md5.sh:

#!/bin/bash echo -n $1 | md5sum | awk '' 

$ md5.sh 123456 e10adc3949ba59abbe56e057f20f883e 

If your system is macOS. You need to modify this script:

$ echo -n 123456 | md5 | awk '' e10adc3949ba59abbe56e057f20f883e 

I created a function md5() < echo -n $1 | md5sum | awk '‘; > in .bashrc and then I can use $ md5 test in the command line. thanks for the answer

openssl md5 filename openssl sha1 filename 

For string pipe the content using echo

echo -n 123456 | openssl md5 

Running md5sum with no arguments at all will cause it to read input from the terminal. Type or paste whatever you want, and when you are done, press ctrl-d to end the input.

@James, if it does not follow a newline, yes. If you hit it after hitting enter, it only needs once. When it does not follow a newline, it just forces all of the characters typed on the line so far to be processed immediately instead of waiting for a newline.

My quick poke at the —help for md5sum demonstrates that the command:

will then give a prompt for simple input. Inputting some text and then using Enter and then Ctrl + D to signify end of file then causes md5sum to spit out the MD5 of the raw text you entered (including that Enter , it’s a CR, IIRC).

Less to type and no piping! And avoiding your plaintext password being recorded in shell history! Woo!

If you do not want that trailing CR (which is usually the case if you want to hash a password), don’t hit Enter before Ctrl + D , enter Ctrl + D twice instead.

There are many examples to do this, but some of them are not equivalent because some of them explicitly or implicitly include the newline, and some others do not.

I would like to clearly specify which of the popular methods includes the newline and which are not.

Here are some examples along to calculating the md5 hash WITHOUT trailing newline (CORRECT):

$ echo -n "test" > test.txt $ wc test.txt 0 1 4 test.txt $ md5sum test.txt 098f6bcd4621d373cade4e832627b4f6 test.txt 

Note: -n in echo means: «do not output the trailing newline».

$ echo -n "test" | md5sum 098f6bcd4621d373cade4e832627b4f6 - 

$ printf "%s" "test" | md5sum 098f6bcd4621d373cade4e832627b4f6 - 

Using only md5sum command:

(Let’s write md5sum , press Enter then write string test and then press double combination Ctrl + d )

$ md5sum test098f6bcd4621d373cade4e832627b4f6 - 

(Let’s write md5sum — , press Enter then write string test and then press double combination Ctrl + d )

$ md5sum - test098f6bcd4621d373cade4e832627b4f6 - 

Here are some examples along to calculating the md5 hash WITH trailing newline (SO NOT CORRECT):

$ echo "test" > test_n.txt $ wc test_n.txt 1 1 5 test_n.txt $ md5sum test_n.txt d8e8fca2dc0f896fd7cb4cb0031ba249 test_n.txt 

Using echo WITHOUT -n inline:

echo "test" | md5sum d8e8fca2dc0f896fd7cb4cb0031ba249 - 

Using only md5sum command but with Enter key after writing the text:

(Let’s write md5sum , press Enter then write string test and then press agaien Enter and once combination Ctrl + d )

$ md5sum test d8e8fca2dc0f896fd7cb4cb0031ba249 - 

Using md5sum — command but with Enter key after writing the text:

(Let’s write md5sum — , press Enter then write string test and then press agaien Enter and once combination Ctrl + d )

$ md5sum - test d8e8fca2dc0f896fd7cb4cb0031ba249 - 

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How to Get md5 Hash Of A File

Message-Digest algorithm, commonly known as md5 hash, is a type of cryptographic hash function mainly used to verify the integrity of files. Md5 is a 128-bit message digest produced after running the MD5 function against a file.

Md5 has its flaws and is therefore not a very good choice for certain encryption methods, but it is very well suited for file verification. It works by creating a checksum of a file and comparing the result to the original. That means if there are changes to a file, there is no way it can produce a digest value similar to the original. The value stays constant no matter where generated or how many times as long as the file remains unchanged.

For this guide, we shall look at ways to generate an md5 hash value of a file. That will allow you to verify the integrity of files either from remote locations or on your local machine.

Install md5sum

In Linux and almost major Unix and Unix-Like systems, they come pre-installed with an md5 tool. The most common one is md5sum. By default, you should find it available in your system.

If you do not have the tool installed, you can use the package manager of your system.

Debian/Ubuntu
On Ubuntu and other Debian based distributions, use apt as:

REHL/CentOS
On REHL and CentOS, use yum as:

Arch/Manjaro
If you are on Manjaro or other arch based distributions, use Pacman using the command:

Fedora
Finally, on Fedora systems, use the dnf command as:

Generate Md5sum of a File

With the tool installed, we can proceed and generate a md5sum for a file. You can use any basic file available in your system. In my example, I am using the /etc/hosts available in Linux systems.

To generate the md5sum of a file, simply use the md5sum command followed by the filename, which you can see in the command below:

The above command should generate a hash value of the file as shown in the output below:

Once the contents of the file change, the md5sum value becomes completely different. For example, add a value to the/etc/hosts file.

Add the following entry to the file (feel free to change to any way you see fit).

If you try to calculate the md5 value of the file with the new contents as:

The hash value is different as shown in the output below:

If you revert the file to its original contents, the md5sum value is similar to the original, allowing you to know when a file has changed.

NOTE: The md5 value will be similar to the original even if the file gets renamed. This is because md5 is calculated based on file contents and not filename.

Verify Online Files

Suppose you want to verify the integrity of a file and ensure it is tamper-proof. To do this, all you need is the original md5 value. In my example, I am using a simple deb package of MySQL from the resource below:

Download the file with wget using the command as:

Once the file has downloaded:

Let us now verify the md5 value using a command:

If the file has not been modified in any way, you should get a similar value as the original as shown:

Conclusion

This tutorial looked at a simple method to verify the md5 checksum of files and verify their modification state.

Here is a quick exercise for you.

Exercise

Create a simple bash script that checks if a file md5 value has any recorded modification every 5 minutes. If the file has changed, delete the file and shut down the system.

That should be a fun exercise!

About the author

John Otieno

My name is John and am a fellow geek like you. I am passionate about all things computers from Hardware, Operating systems to Programming. My dream is to share my knowledge with the world and help out fellow geeks. Follow my content by subscribing to LinuxHint mailing list

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Generating Hashes From Bash and Terminal (SHA1, MD5 or SHA256. Etc.)

How to generate, and compare hashes from terminal using bash and PHP scripts in Linux.

Sometimes I have had the need to generate a hash, be it MD5, SHA1 or sha256. In the past, I would do this from a PHP file, which i would then load via my browser. This is, however, hugely inefficient! So, I decided to look into how it could be done directly from a terminal in Linux.

This would appear not to be very obvious how to do, although I realized how do it later after much searching online.

In Linux, we have so-called «man» pages telling us how to use different commands. Using them takes some getting used to, as they are not very readable. However, they can still be helpful when trying to learn about commands used in bash scripting. To use it, simply type man followed by whatever command you want more information on:

To generate a hash from terminal, one can use the hash functions:

md5sumtest sha1sumtest sha256sumtest 

They also work for downloaded files, which can be useful when you need to verify a package has not been tempered with:

If you are not currently in the Downloads folder, you can also type the path for the file, instead of first navigating to the ~/Downloads folder:

md5sum ~/Downloads/file-name.zip

This is all fine. But, what if you want to generate a hash from a CLI script? I do not really care what scripting language you use. You can use Bash if you are comfortable with that. Personally, I prefer the syntax in PHP scripts, but I am also learning to use Bash.

CLI Scripting

If you need to generate a hash from bash, things become more complicated. This is because extra characters might be added to your string, depending on circumstances. Both Bash and PHP scripts accept arguments. In PHP, they can be accessed via the $argv array:

The #!/usr/bin/php part tells the system to use the php binary to execute the script. The PHP scripts themselves can also be placed in /usr/bin, which makes them callable from anywhere. I would typically create a symbolic link for the original file, rather than having the script itself placed in /usr/bin.

The above can also be done in bash, and might look like this:

In bash, arguments are available in the $1, $2, $3, etc. Variables.

You could also ask the user a question, and then accept the string as input. But, since echo adds a newline character, the hash sum would be incorrect. The newline can be removed with -n (See: man echo in a terminal):

#!/bin/bash # This script generates a md5sum from a string echo "Type or Paste the String and hit enter to generate a md5 sum." read inputString echo -n $inputString | md5sum

The pipe character (Vertical Bar), can be used to take the output of one command (in this case echo), and serve it to another command. In this case, the first command getting executed is actually the echo command. The result from echo is then passed on to md5sum, and shown in the terminal.

You can test the above by excluding -n, which will result in a incorrect hash sum (the one with newline added).

Compare hash values with a bash script

Lets say you want to compare the hash sum of a downloaded file with hash’es found on the website, to verify the integrity of the download. Creating a bash script with a simple if statement would be enough.

#!/bin/bash echo 'Supply your hash below (copy & paste):' read inputHash fileHash=($(md5sum $1)) if [ $inputHash = $fileHash ] then echo -e '\nMatched. The strings were:\n' echo $inputHash echo $fileHash else echo -e 'WARNING: NO MATCH!\n' echo 'The file could be compromised. If you downloaded the file, you should try re-downloading it.' fi 

To use this script, simply do ./md5.sh some_file_name.iso

As you can see from the above, the syntax is not very nice, and takes some getting used to. The above can also be done with PHP, arguably in a more readable way.

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