Piet --
...and then Piet Delport said...
% On Fri, 14 Sep 2001 at 07:03:19 -0400, David T-G wrote:
% > % ---BEGIN---
% > % #!/bin/sh
% > ...
% > % pgp $* 2>$PGP_ERR 1>$PGP_OUT
...
% > pgp ${1+"$@"} 2>$PGP_ERR 1>$PGP_OUT
% >
% > and you're golden.
%
% It's much more straightforward to use:
%
% pgp "$@" [...]
%
% actually. :)
Oh, really? Cool!
Actually, that looks familiar... I wonder if I tried that under Solaris
and found it to not work, 'cuz I would have otherwise stripped down to
it.
%
% > [BTW, I haven't *yet* found this in any shell documentation since I
% > saw it in a shell programming tip; can anyone provide me a pointer for
% > further research?]
%
% I daresay you haven't been looking hard enough. :)
Well, there's always someone to say that.
%
% Quoting FreeBSD's "man sh" [from the listing of special parameters]:
% | @ Expands to the positional parameters, starting from one.
% | When the expansion occurs within double-quotes, each
% | positional parameter expands as a separate argument. If
% | there are no positional parameters, the expansion of @
% | generates zero arguments, even when @ is double-quoted.
% | What this basically means, for example, is if $1 is ``abc''
% | and $2 is ``def ghi'', then "$@" expands to the two
% | arguments:
% | "abc" "def ghi"
Aha! I don't use BSD (yet), so I don't have access to that, or at least
hadn't thought to search the web for a copy of the freebsd sh man page.
My linux system doesn't even have a man page for sh, preferring info or
whatever it is, and Solaris doesn't mention it at all.
%
% As for further research, i generally got by on the sh and bash manpages
% up till now. They're generally very concentrated in terms of info, and
Yep; I've learned a lot since first trying out "man man".
% take a while to sink in. I find myself realizing new things all the
% time when i'm (re-)reading them. :-)
That's fun :-)
%
% (Prominent example: just now while writing this mail, i saw for the
% first time how ${1+"$@"} works. Ingenious approach, even if a bit
I see that "$@" protects argument expansion; what does the 1 mean? And I
don't have a Solaris box handy to look in a man page to reference what +
means; I only use :- on a regular basis.
% redundant. Most probably in the context of the tip you found it in it
% was a workaround for a shell that didn't handle a plain "$@" correctly?)
It was in a SysAdmin book and simply included in a shell script example
without any further comment. Weird, eh?
%
% --
% Piet Delport <[EMAIL PROTECTED]>
% Today's subliminal thought is:
Thanks for the info!
:-D
--
David T-G * It's easier to fight for one's principles
(play) [EMAIL PROTECTED] * than to live up to them. -- fortune cookie
(work) [EMAIL PROTECTED]
http://www.justpickone.org/davidtg/ Shpx gur Pbzzhavpngvbaf Qrprapl Npg!
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