GNU bug report logs - #17997
md5sum adds a new line at the end of the input

Previous Next

To add a comment to this bug, you must first unarchive it, by sending
a message to control AT debbugs.gnu.org, with unarchive 17997 in the body.
You can then email your comments to 17997 AT debbugs.gnu.org in the normal way.

Toggle the display of automated, internal messages from the tracker.

Message #5 received at submit <at> debbugs.gnu.org (full text, mbox):

From: xavier.richez <at> laposte.net
To: bug-coreutils <at> gnu.org
Subject: md5sum adds a new line at the end of the input
Date: Fri, 11 Jul 2014 10:48:30 +0200

[Message part 1 (text/plain, inline)]

Hello,

I implemented my own MD5 generator.
It provides the same results as all the online MD5 generators, like for instance http://onlinemd5.com/.

But it gives a different result than the GNU md5sum tool.
So I investigated this : it seems that md5sum adds a newline at the end of the input !

That is quite easy to test :
- go to http://onlinemd5.com/, type "test" as text input. The MD5 sum is 098f6bcd4621d373cade4e832627b4f6
- now type in a prompt : "echo test | md5sum". The MD5 sum is d8e8fca2dc0f896fd7cb4cb0031ba249
- back to onlinemd5.com, type "test" and press enter to add a new line in the input. Now the MD5 sum is d8e8fca2dc0f896fd7cb4cb0031ba249 !!

This behaviour was detected on RedHat Enterprise Linux 6.3 with GNU Coreutils 8.4.
I was able to reproduce it using the latest 8.22 version (fresh build) on the same machine, and on CentOS 5.10 with Coreutils 5.97.

Did someone know about this ?

Best regards,
Xavier Richez.

[Message part 2 (text/html, inline)]

Message #8 received at 17997 <at> debbugs.gnu.org (full text, mbox):

From: Pádraig Brady <P <at> draigBrady.com>
To: xavier.richez <at> laposte.net
Cc: 17997 <at> debbugs.gnu.org
Subject: Re: bug#17997: md5sum adds a new line at the end of the input
Date: Fri, 11 Jul 2014 16:45:03 +0100

tag 17997 notabug
close 17997
stop

On 07/11/2014 09:48 AM, xavier.richez <at> laposte.net wrote:
> Hello,
> 
> I implemented my own MD5 generator.
> It provides the same results as all the online MD5 generators, like for instance http://onlinemd5.com/.
> 
> But it gives a different result than the GNU md5sum tool.
> So I investigated this : it seems that md5sum adds a newline at the end of the input !
> 
> That is quite easy to test :
> - go to http://onlinemd5.com/, type "test" as text input. The MD5 sum is 098f6bcd4621d373cade4e832627b4f6
> - now type in a prompt : "echo test | md5sum". The MD5 sum is d8e8fca2dc0f896fd7cb4cb0031ba249
> - back to onlinemd5.com, type "test" and press enter to add a new line in the input. Now the MD5 sum is d8e8fca2dc0f896fd7cb4cb0031ba249 !!
> 
> This behaviour was detected on RedHat Enterprise Linux 6.3 with GNU Coreutils 8.4.
> I was able to reproduce it using the latest 8.22 version (fresh build) on the same machine, and on CentOS 5.10 with Coreutils 5.97.
> 
> Did someone know about this ?

echo adds the newline.

  $ printf 'test' | md5sum
  098f6bcd4621d373cade4e832627b4f6  -

thanks,
Pádraig.

Message #15 received at 17997-done <at> debbugs.gnu.org (full text, mbox):

From: Eric Blake <eblake <at> redhat.com>
To: xavier.richez <at> laposte.net, 17997-done <at> debbugs.gnu.org
Subject: Re: bug#17997: md5sum adds a new line at the end of the input
Date: Fri, 11 Jul 2014 09:47:12 -0600

[Message part 1 (text/plain, inline)]

tag 17997 notabug
thanks

On 07/11/2014 02:48 AM, xavier.richez <at> laposte.net wrote:
> Hello,
> 
> I implemented my own MD5 generator.
> It provides the same results as all the online MD5 generators, like for instance http://onlinemd5.com/.
> 
> But it gives a different result than the GNU md5sum tool.
> So I investigated this : it seems that md5sum adds a newline at the end of the input !

No, YOU are adding a newline into the input you are feeding to md5sum.

> 
> That is quite easy to test :
> - go to http://onlinemd5.com/, type "test" as text input. The MD5 sum is 098f6bcd4621d373cade4e832627b4f6
> - now type in a prompt : "echo test | md5sum". The MD5 sum is d8e8fca2dc0f896fd7cb4cb0031ba249

Try this:
echo test | od -tx1z
printf test | od -tx1z

Notice the difference?  If you use echo, you are passing a newline into
md5sum, and md5sum is doing the right thing.  Use printf instead of
echo, and you will get the results you want.

As this is a usage error and not a bug, I'm closing this report.  But
feel free to ask further questions as needed.

-- 
Eric Blake   eblake redhat com    +1-919-301-3266
Libvirt virtualization library http://libvirt.org

[signature.asc (application/pgp-signature, attachment)]

Previous Next

GNU bug tracking system
Copyright (C) 1999 Darren O. Benham, 1997,2003 nCipher Corporation Ltd, 1994-97 Ian Jackson.