On 06/28/2010 07:08 PM, Malcolm Kay wrote: > Eric, > Thanks for the clarification. > > I had assumed that 'dash' aimed to be a faster replacement for > the classical Bourne shell 'sh' as implemented in BSD systems, Rather, 'dash' aims to be the fastest and smallest possible POSIX-compliant shell; anywhere that POSIX disagrees with traditional Bourne shell behavior, POSIX triumphs. Not all BSD system /bin/sh are POSIX compliant. And while dash has some extensions over POSIX, the goal of being smallest means that extensions are kept to a minimum (contrast that with bash or zsh, which both have a goal of providing as many useful extensions as possible at the expense of size and sometimes speed). > As it is I feel the man pages should not only be fixed in this > respect, but also such differences to classical 'sh' > implementations should be high lighted. There are other existing online resources that describe differences between Bourne shell and POSIX. But it is a much bigger effort to document how dash differs from non-POSIX shells than it is to just document how dash itself behaves. > > On Mon, 28 Jun 2010 10:52 pm, Eric Blake wrote: >> . . . >> >> Therefore, the bug is in the man page. Per POSIX, >> http://www.opengroup.org/onlinepubs/9699919799/utilities/V3_ch >> ap02.html#tag_18_09_03 "A list is a sequence of one or more >> AND-OR lists separated by the operators ';' and '&' and >> optionally terminated by ';' , '&' , or <newline>." > > While I agree with your conclusions, I would note that POSIX > defines "if ... else etc." in terms of 'compound_list' rather > than 'list' so the above definition of 'list' is not really > relevant. By my reading of your reference it seems POSIX defines > 'list' and 'compound_list' independently but fails to clarify > the difference if any. POSIX defines compound_list quite clearly. Read the grammar section: http://www.opengroup.org/onlinepubs/9699919799/utilities/V3_chap02.html#tag_18_10_02 compound_list : term | newline_list term | term separator | newline_list term separator It also defines list: list : list separator_op and_or | and_or The difference between the two is how newlines serve to separate the various and_or lists. -- Eric Blake eblake@xxxxxxxxxx +1-801-349-2682 Libvirt virtualization library http://libvirt.org
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