Hello,
as another member of this list kindly pointed out, it was a
misunderstanding of mine to assume misbehavior in parallel. Sorry for that!
From the (mostly private) communication, i offer the following
"compilation":
Initial post:
hello,
far from being a power user with linux...
... i happen to play with parallel...
and get confused/surprised at times. Like so:
echo this should not happen | xargs -n 1 echo | parallel --dry-run -n 2 echo
`echo {}`
First, i was not able to separate the 4 words into different arguments with
--colsep ' ', so that is why i used xargs in the mix.
Then, i did not expect --dry-run to allow for execution of the embedded `echo`
command.
Ok, i can imagine scenarios, when this comes in handily...
My current conclusion is: be VERY careful with this powerful tool, test
thoroughly before execution but even then... (can i trust it?) beware of
unexpected side-effects.
just my 2 cents
what i intended to see could instead be produced with the following command:
echo -n "this should not happen" | parallel --dry-run -d ' ' -n 2 echo \`echo
{}\`
which produces:
echo `echo this should`
echo `echo not happen`
which in turn could be piped to a shell.
This is to show:
with proper escaping and parameters, it is indeed possible to get what
my initial intention had been. Sorry for being confused and initially
blaming outward.
best regards, C.D.
