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

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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

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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

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