lackita has asked for the wisdom of the Perl Monks concerning the following question:

Here is the code that isn't working: 
open(LS, qq{/usr/local/openssh/bin/ssh -p 22 foo\@localhost "if [ -d /
+home/foo/bar/20110826 ] ; then echo 1 ; else echo 0 ; fi" |});
my $baz = <LS>;

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The code hangs on me indefinitely. The strange thing is that, if I put it in a one-liner, it runs fine. Any ideas?

EDIT: I found the issue. The code had set 

local $SIG{CHLD} = sub {
    1 until waitpid(-1 , WNOHANG) == 1;
};

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to solve another issue, and this caused the process to sit in an infinite loop after termination.

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Re: open on ssh command stuck
by onelesd (Pilgrim) on Aug 26, 2011 at 23:12 UTC
    Working for me. But, if <LS> is hanging it has to be because no \n is received. Add 2>&1 to the open command, maybe you are getting an error you aren't seeing due to not capturing STDERR. 
    #!/usr/bin/perl
open(LS, qq{ssh -p 22 onelesd\@localhost "if [ -d /home/foo/bar/201108
+26 ] ; then echo 1 ; else echo 0 ; fi" 2>&1 |});
my $baz = <LS>;
print $baz ;

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    MacBook-Pro:Downloads onelesd$ ./script.pl 
0
MacBook-Pro:Downloads onelesd$

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      That didn't seem to help. How would I be able to cause a \n to be received?
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