Re: question about zargs

[Bart Schaefer <schaefer@xxxxxxxxxxxxxxxx>]

Preface for Han Pingtian:  If the command you're going to run is external
to the shell, then I recommend you use xargs.  However, in some cases it
may be desirable to get xargs-like behavior when passing arguments to a
shell function or builtin, which is why there is zargs.

On Oct 31,  2:25pm, Peter Stephenson wrote:
} Subject: Re: question about zargs
}
} Hmm... in principle, you can do:
} 
} zargs -n2 **/* -- ls
} 
} so that it executes ls and one additional argument each time.  This is
} equivalent to the -n1 you gave to xargs.

Well, yes and no.  zargs -n2 is not "equivalent to" xargs -n1 in the
general case.  In the previous thread about this, it was pointed out that

    zargs -n2 **/* -- ls -l

is equivalent to

    zlargs -l1 **/* -- ls -l

But the only reason you need -n2 is because of the "-l" that is already
trailing the "ls" command.  If there are no trailing arguments (that is,
the command is a name only) then -n1 and -l1 are equivalent.
 
} However, with a lot of iles this is running incredibly slowly for me and
} after a few dozen files have been processed I hit:
} 
} 279: mem.c:1180: MEM: allocation error at sbrk, size 589824.
} zargs:279: fatal error: out of memory

Hmm, "a few dozen" isn't nearly enough to trigger this for me, though if
I run it on a sufficiently large set of files I can watch the memory
usage of the shell grow steadily throughout.

And yes, it can be slow.

If I try

    zlargs -l1 **/* -- print > /dev/null

the memory use jumps much faster, probably because no forking is involved.

-- 
Barton E. Schaefer