xargs enhancement: I collect new args while the last set is running, use a fixed common buffer for input, and vary the arg count down for long args.

dgp@dgp-p6803w:~

$ fxargs2

Usage: fxargs2 [ -n <args_per_exec> ] [ -v ] [ -p ] <cmd> [ <cmd_arg> ... ]

Reads arguments as lines from standard input and executes:

Each line becomes one argument. The number of args per command is limited

by <args_per_exec> (default 1024). The command is executed when either:

- the total number of args from standard input is <args_per_exec>, or

- the buffer has ( 80 * <args_per_exec> ) unexecuted bytes of input, or

- stdin EOF is detected with any args from standard input.

The <cmd> [ <cmd_args> ... ] is never executed alone.

The buffer is fixed in size at 80 * <args_per_exec>, so long args can force

fewer <args_per_exec> for any pass.

While a command is executing, reading resumes, but before another command

is executed, the prior command must return a status.

With -v, any abnormal child state returned is reported.

With -p, any child terminating on SIGPIPE causes a normal exit.

dgp@dgp-p6803w:~

$

I was tempted to exec more often if stdin was temporarily dry, but better is the enemy of good enough!

-----Original Message-----
From: Paul Jackson <pj@usa.net>
To: David G. Pickett <dgpickett@aol.com>; eggert@cs.ucla.edu <eggert@cs.ucla.edu>; 60506@debbugs.gnu.org <60506@debbugs.gnu.org>
Sent: Tue, Jan 3, 2023 5:32 pm
Subject: Re: bug#60506: feature: parallel grep --recursive

David Pickett wrote:

<< I also wrote a simpler, line oriented, faster xargs, fxargs! >>

I've been quite pleased with an xargs wrapper I wrote that basically

converts newlines to nuls, and then invokes either "xargs" or, if asked

to run multiple threads, "parallel --xargs", passing all the "xargs" arguments

to "xargs --null".

I got all the exit status's and such just right, and preferred having all the

xargs options available, once this hack worked around the confused

space character handling of xargs without the --null option.

I call my wrapper "x", a short name since I use it a lot, having been a regular

xargs user since it was added to Version 7 Unix, inside Bell Labs, back around

1978.

You can find my wrapper at:

http://thepythoniccow.us/x.c

By the way, even the original author of xargs, Herb Gellis, agrees that its

interface is somewhat borked. See a note Gellis posted a decade after writing

xargs, which I include in the above "x.c" source. An amusing bit of history ...

-- 
                Paul Jackson
                pj@usa.net