Date: Wed, 16 Oct 2002 09:30:05 -0700 (PDT) From: Alexandr Kovalenko <never@nevermind.kiev.ua> To: freebsd-bugs@FreeBSD.org Subject: Re: bin/44142: /bin/sh does not support 'command1 & && command2' syntax, which is REQUIRED by POSIX Message-ID: <200210161630.g9GGU5SN054457@freefall.freebsd.org>
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The following reply was made to PR bin/44142; it has been noted by GNATS. From: Alexandr Kovalenko <never@nevermind.kiev.ua> To: Garrett Wollman <wollman@lcs.mit.edu> Cc: FreeBSD-gnats-submit@FreeBSD.ORG Subject: Re: bin/44142: /bin/sh does not support 'command1 & && command2' syntax, which is REQUIRED by POSIX Date: Wed, 16 Oct 2002 19:26:12 +0300 Hello, Garrett Wollman! On Wed, Oct 16, 2002 at 11:55:42AM -0400, you wrote: > > /bin/sh does not support 'command1 & && command2' syntax, which is REQUIRED by POSIX: > > Your interpretation is erroneous. The grammar takes precedence over > the textual description of the syntax, and the grammar is quite clear: > > complete_command : list separator > | list > ; > list : list separator_op and_or > | and_or > ; > and_or : pipeline > | and_or AND_IF linebreak pipeline > | and_or OR_IF linebreak pipeline > ; As we can see from Grammar: pipeline : pipe_sequence | Bang pipe_sequence ; pipe_sequence : command | pipe_sequence '|' linebreak command ; So, we can parse 'command1 & && command2' in this way: 'command1 & && command2' : and_or(complete_command(list('command1') separator(' ')) separator_op('&') AND_IF pipeline('command2')) > The pseudo-syntax `command1 &' can only be resolved by the `list' > production in the grammar. The `&&' and `||' operators take > pipelines, and not lists, as operands. See XCU6 page 58. Yes. It is correct. Sorry for false alert. -- NEVE-RIPE Ukrainian FreeBSD User Group http://uafug.org.ua/ To Unsubscribe: send mail to majordomo@FreeBSD.org with "unsubscribe freebsd-bugs" in the body of the message
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