Re: [Haskell-cafe] [offtopic] UNIX Shell (was: GHC RTS question)

* Magnus Therning [2010-02-24 09:11:54+0000]

On Wed, Feb 24, 2010 at 07:18, Roman Cheplyaka wrote:

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* Brandon S. Allbery KF8NH [2010-02-24 00:02:12-0500]

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On Feb 22, 2010, at 03:36 , Roman Cheplyaka wrote:

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* Anthony Cowley [2010-02-21 14:15:00-0500]

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#! /usr/bin/env bash ./prog --RTS $*

./prog --RTS "$@"

Otherwise it will work wrong if arguments contain quoted field separators (e.g. spaces).

  #! /bin/sh   ./prog --RTS ${1+"$@"}

The longer specification above should work with whatever /bin/sh is around, whether it's Solaris /sbin/sh, FreeBSD's sh, general Linux bash, Debian/Ubuntu dash, etc.

Are you referring to some Solaris shell bug?

Under POSIX these constructs seem to be equivalent. "If there are no positional parameters, the expansion of '@' shall generate zero fields, even when '@' is double-quoted."

I believe he's referring to the following bit (taken from bash's man page):

@ Expands to the positional parameters, starting from one. When the expansion occurs within double quotes, each parameter expands to a separate word. That is, "$@" is equivalent to "$1" "$2" ... If the double-quoted expansion occurs within a word, the expansion of the first parameter is joined with the beginning part of the original word, and the expansion of the last parameter is joined with the last part of the original word. When there are no positional parameters, "$@" and $@ expand to nothing (i.e., they are removed).

Well, this agrees with POSIX. So still I don't see the difference between "$@" and ${1+"$@"}. -- Roman I. Cheplyaka :: http://ro-che.info/ "Don't let school get in the way of your education." - Mark Twain