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why the following two opens have different result?

open(PS,"ls . 2>/dev/null |")

[download]
is equivalent to 
open(PS, '-|', /bin/sh', '-c', 'ls . 2>/dev/null ')

[download]
but 
open(PS,"ls . |")

[download]
get optimised to 
open(PS, '-|', 'ls', '.')

[download]

Also see the update to my original reply.

But how can i get the exit status for the command in this case?

You already know how. It's in $? after a successful close. In this case, it's 141. The shell returns 141 (128|SIGPIPE) when its child dies from SIGPIPE.

In reply to Re^3: How to know the status of a command invoked by open function? by ikegami
in thread How to know the status of a command invoked by open function? by zhujian0805

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