Re: Trying to understand man page for dd
On 05/29/2017 01:20 AM, Thomas Schmitt wrote:
Hi,
David wrote:
https://explainshell.com/explain?cmd=dd+if%3D%2Fdev%2Fzero+of%3D%2Fdev%2Fnul
l%26+pid%3D%24!
For a machine this is not a bad answer.
https://explainshell.com/explain?cmd=kill+-USR1+%24pid%3B+sleep+1%3B+kill+%24pid
But this one missed the point quite clearly.
(It gets no clue that the signals are sent to dd. So the result can
only be unspecific info.)
His post did have impact.
It reminded me of <https://explainshell.com>. I've used it a few times
but it hadn't come to mind. If I had remembered, I would have asked a
different {better????} question.
Your reply then caused me to re-read slowly and _carefully_ your
previous post.
I think the is a subtle bug in the man page.
I introduces the two lines of code saying:
> Sending a USR1 signal to a running 'dd' process makes it print
> I/O statistics to standard error and then resume copying.
I believe that to accurately describe the code at
https://www.gnu.org/software/coreutils/manual/html_node/dd-invocation.html#dd-invocation
*NOT* the code on the man page.
I realize now that was the discrepancy that prompted my question.
I had gone to the man page to double check syntax. Spotted the code a
thought "a way to display progress information when copying".
I can "sort of" understand syntactically correct code. The less said of
my programming skills the better ;/ How I "read" the code just didn't
jibe with the description.
Am I correct that there is a problem with the man page?
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