".GIF" files

Ed Horch ebh at argon.UUCP
Tue Feb 26 03:37:03 AEST 1991


In article <996 at gnosys.svle.ma.us> gst at gnosys.svle.ma.us (Gary S. Trujillo) writes:
>In <843 at argon.UUCP> ebh at argon.UUCP (Ed Horch) writes:
>> There may be a performance cost due to creating an additional
>> process for "cat a", but a smart shell will know how to short-
>> cut around that.
>
>What's this about a "smart shell"?  I've never heard of a shell that
>optimizes commands.  It seems inherantly very difficult to recognize
>that the two commands listed above are equivalent, since it requires
>a knowledge of what cat(1) does.  What shell are we talking about here?

The Korn Shell has subsumed several common commands as shell builtins.
I stand corrected on one point - cat isn't one of them, but echo and
test are, among others.  Yes, it does have knowledge about what those 
commands do.  The shell decides whether to perform any task either 
inline, in a subshell, or in a subprocess, depending upon what would 
be most optimal.

-Ed



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