Re: Package maintainer script policy.
Hi,
>>"Anselm" == Anselm Lingnau <lingnau@tm.informatik.uni-frankfurt.de> writes:
Anselm> Raul Miller wrote:
>> > How many people actually understand what ${1+"$@"} does, really?
>>
>> Interesting question. I thought it meant exactly the same thing
>> as "$@". Why?
Anselm> There used to (?) be shells that were so utterly broken that "$@"
Anselm> wouldn't work if there was only one argument, so you had to use the
Anselm> other idiom instead.
No, not quite.
Actually, the problem is that you need to quote $@ so the
contents are not evaluated before they are needed. Consider what
happens if I say
% exec some-prog $@
My shell expands $@. now, if $@ contains some shell meta
characters, like say `;' or even `\;' we may have problems (in the
first case, exec is onlyu going to get part of the arguments to pass
on, and we shall try to eval the rest as another command)
So, I have to say, at least,
% exec some-prog "$@"
Now, suppose some-prog counts its arguments (we don't know, in
genral, do we?), and does different things when there are no
arguments (go into interactive mode, for example).
Well, if $@ is empty, "$@" expands to ""; which is not the
same as no arguments!! So there is no way to pass the fact that ther
were no arguments, unless,
% exec some-prog ${1+"@"}
How this works is left as an exercise for the user.
manoj
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Manoj Srivastava <srivasta@acm.org> <http://www.datasync.com/%7Esrivasta/>
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