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

[Magnus Therning]

On Wed, Feb 24, 2010 at 07:18, Roman Cheplyaka <roma at ro-che.info> wrote:
> * Brandon S. Allbery KF8NH <allbery at ece.cmu.edu> [2010-02-24 00:02:12-0500]
>> On Feb 22, 2010, at 03:36 , Roman Cheplyaka wrote:
>> >* Anthony Cowley <acowley at seas.upenn.edu> [2010-02-21 14:15:00-0500]
>> >>#! /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, it expands to a single word with the value of
  each parameter separated by the first character of the  IFS  special
  variable.   That  is, "$*" is equivalent to "$1c$2c...", where c is the first
  character of the value of the IFS variable.  If IFS is unset, the parameters
  are separated by spaces.  If IFS is null, the parameters are joined without
  intervening separators.
@ Expands to the positional parameters, starting from one.  When the expansion
  occurs within double quotes, each parameter expands to a separate word.  That
  is, "$@" 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).

/M

-- 
Magnus Therning                        (OpenPGP: 0xAB4DFBA4)
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