On Sun, Jan 5, 2014 at 11:09 AM, Linda A. Walsh <g...@tlinx.org> wrote:
>
>
> James Youngman wrote:
>>
>> You can use the "sh -c" trick to run the first argument as the command.
>>
>
> ----
> Do you think the above case could be optimized? As I mentioned in my inital
> query, I wanted to avoid shell overhead on 80 thousand sub-jobs.
You have 80,000 lines (=80k commands to run from xargs) or 80,000
command-line srguments? If the latter, how many commands?
> I.e. is there any reason xargs couldn't run the arguments directly -- i.e.
> taking the first word of input as a program to run and either do a path
> lookup, OR require an absolute path (either would be fine)
I'm reluctant for the usual reasons
1. I think thjs is a niche use case
2. It imposes documentation, testing and maintenance effort out of
proportion (ass far as I can see at the moment, though I am willing to
change my mind) to its usefulness
Plus another reason:
3. The usual execution model of xargs is to run a trusted command on
potentially untrusted arguments. This widens the exposure somewhat,
because the command being run may also not be trusted.
>> You can use -d to select the delimiter.
>>
>
> ----
> That will work.. didn't see it would override the normal quote
> processing... Thanks!
If the documentation isn't clear I should fix it. If you'd like to
suggest a specific change (to both the manual page and the Texinfo
documentation) that would be useful.
> I looked at 'parallel' and 'sem' as well, and they want a command on
> the command line as well... geez... you'd think something would
> take a list of command in a file and run them in parallel (subject
> to load constraints) w/o having to run a shell w/each command.
batch(1) does this (though you would need to split the input and it
probably uses a shell to launch the command).
>
> Hard to believe such a simple thing wouldn't be an option...but
>
> is there any reason why putting a "-I {}" by itself on the command
> line shouldn't work?
If you specify zero initial arguments, the default is "echo".
> (tried "exec", but I guess that is a shell builtin...sigh)...
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