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Old 04-06-2016, 02:19 PM   #1
pradeepspa
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What is "ps | md5sum"


Hi all,

as far I know md5sum generate a number which is used to check the integrity of file between source and destination. However when i run this command,
"ps awx | md5sum", I am getting md5 code which keeps changing everytime the mentioned command is ran . Could someone explain what is md5sum is doing with respect to ps command?

Thanks in Advance.
 
Old 04-06-2016, 02:39 PM   #2
suicidaleggroll
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md5sum, when provided with data on stdin, will generate the checksum of that data regardless of what it is. For example:
Code:
echo "hat" | md5sum
will return the md5 hash for the string "hat", which is "80c7384a6339a053baee278cb13e578c", and it will be the same every time you run it.

When you run "ps awx | md5sum", you're computing the md5 hash of the output of "ps aux". Since the output of "ps aux" is different every time you run it (processes starting/stopping, different runtimes for existing processes, etc.), naturally the md5 hash will be different as well.

Last edited by suicidaleggroll; 04-06-2016 at 02:44 PM.
 
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Old 04-06-2016, 03:20 PM   #3
pradeepspa
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Thanks for the explanation. Helped me lot. What is the purpose of generating md5sum for ps?
 
Old 04-06-2016, 03:25 PM   #4
schneidz
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Quote:
Originally Posted by pradeepspa View Post
Thanks for the explanation. Helped me lot. What is the purpose of generating md5sum for ps?
its the digital equivalent of paying someone to dig a hole and paying someone else to fill it.
 
Old 04-06-2016, 03:29 PM   #5
pradeepspa
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ah gotcha. Thanks all
 
Old 04-06-2016, 04:59 PM   #6
Markx7
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Quote:
Originally Posted by pradeepspa View Post
What is the purpose of generating md5sum for ps?
Probably they're just experimenting with md5sum. There's no value doing a md5sum on the output of ps unless they just wanted to generate a string of characters to use for something else.

I look at md5sum as a quick way of signing files and checking the sums. I prefer to use GPG to sign files and use a signature key to verify the integrity of my files.

Last edited by Markx7; 04-06-2016 at 05:00 PM.
 
Old 04-07-2016, 12:15 PM   #7
sundialsvcs
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They might have thought of it as "a random string," on the presumption that the output of "ps" would never be exactly the same. But, I don't like to see code that incorporates either "assumptions" or "cleverness."
 
Old 04-07-2016, 04:02 PM   #8
pradeepspa
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I have actually found that in a script. I will dig further to see why exactly it was used for
 
Old 04-07-2016, 05:51 PM   #9
suicidaleggroll
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They might be using it as some kind of pseudo random number generator, but there are better ways if that's the end goal.
 
  


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