I didn't mean to imply there was anything underhanded about McIlroy's critique. Just that that, because McIlroy's code isn't trying to solve the same problem, it shouldn't be taken as a rebuttal to Knuth's point, which is what, apparently, many people believe it to be.
There's lots of interesting facets here. Doug's solution requires a working Unix system. You might not have that in the problem space.
On the other hand, his solution shows that by assuming some nice things about your data, things which Pascal does not allow, you can do some useful things with terse programming. This is reminiscent of the array programming model of APL or J. I haven't written a solution but I'd be surprised if it is more than about 15 characters.
In the shell case, the terse program is like a Chinese classic. Written in its own jargon requiring basically a prior understanding of the program to read it.
> In the shell case, the terse program is like a Chinese classic. Written in its own jargon requiring basically a prior understanding of the program to read it.
However, if Knuth wanted to be terse, he could have been and write a Pascal program which uses his library routines without showing them ! -- in effect using Unix solution by Doug is equivalent to "not only you must use already pre-written libraries in order to be terse, they are even not the plain routines but they are instead packed as the whole executables, and to use these executables you have to use them on exactly this operating system, exactly using this specific shell, all that property of AT&T (at that time Linux didn't exist, and who had rights to use what wasn't clear, unless you've bought something expensive) just to be able to call these library routines.
So it can't be considered a serious "critique." At that time, under these circumstances, it was just an unfair ad.
