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Old 28th June 2013
thirdm thirdm is offline
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Join Date: May 2009
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Default Bourne pipe operator parse ambiguity?

I'm puzzled by this statement: "It is remarkable that in the four most recent editions of the UNIX system programmer’s manual the Bourne shell grammar described in the manual page does not admit the command who|wc. This is surely an oversight, but it suggests something darker: nobody really knows what the Bourne shell’s grammar is." -- http://doc.cat-v.org/plan_9/4th_edition/papers/rc

Reading the sh manual on NetBSD, the only other use of the pipe symbol I could find was in case statements to give multiple patterns in each alternative. I don't get what problem that could create. Does anyone know what Tom Duff is getting at?
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