I do not consider that to be a fault with the ERASE command; in fact, quite the 
contrary is true. In addition, it does not address the original question, which 
was in essence, if filea is not present, erase fileb. For a single file, I 
would think that a sequence of commands, 'STATE filea'; if rc ^= 0 then 'ERASE 
fileb' would be inherently more efficient than invoking PIPELINES to do the job 
and would be clearer to any novice programmer reading the code. Why use a 
sledge hammer to drive a tack or a bulldozer to move a pebble? Your solution is 
what I consider to be a misuse of Pipes.

Besides, if FOO BAR A does not exist, your pipeline will fail at the first 
stage. The suggested Pipe using STATE does not have this failing, but even it 
is overkill for a single file.

Regards, 
Richard Schuh 

 

> -----Original Message-----
> From: CMSTSO Pipelines Discussion List 
> [mailto:[email protected]] On Behalf Of Paul Gilmartin
> Sent: Tuesday, November 23, 2010 6:29 PM
> To: [email protected]
> Subject: Re: Treating absent files as empty
> 
> On Nov 23, 2010, at 10:08, Schuh, Richard wrote:
> 
> > Is there something wrong with the ERASE command?
> >
> Yes, there is something wrong with ERASE.  Consider:
> 
>     PIPE < FOO BAR A | LOCATE something | > FOO BAR A
> 
> -- gil
> 

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