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'system' anomaly in perl-5.8.9

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James E Keenan
January 26, 2020 03:23
'system' anomaly in perl-5.8.9
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I am trying to understand an anomaly in a usage of 'system' observed in 
perl-5.8.9 -- but not in (most? all?) other production releases of perl.

Given: the attached program, '' -- which I'll place in '/tmp' 
for convenience but which derives from CPAN distribution 
IPC-System-Simple's test suite;

Given: a variety of different installed perl executables, including at 
least 5.8.9 -- for convenience I'll use my executables installed via 

Then, running via a 'system' call from each of the 
executables results in a value of '$?' of '134' for all versions except 
5.8.9, where the value of '$?' is '6'.

I know that this is so on Linux, but I can't rule out its happening on 
other OSes.

The attached shell script,, can be used to demonstrate the 
problem (assuming you have 'perlbrew' installed and have installed 
several versions of perl thereby).  When I run this script, these are my 

$ ./
perl-5.30.0     /tmp/  134
perl-5.28.0     /tmp/  134
perl-5.26.2     /tmp/  134
perl-5.24.4     /tmp/  134
perl-5.22.3     /tmp/  134
perl-5.22.2     /tmp/  134
perl-5.22.0     /tmp/  134
perl-5.20.3     /tmp/  134
perl-5.20.1     /tmp/  134
perl-5.20.0     /tmp/  134
perl-5.18.4     /tmp/  134
perl-5.18.2     /tmp/  134
perl-5.16.3     /tmp/  134
perl-5.14.4     /tmp/  134
perl-5.12.5     /tmp/  134
perl-5.10.1     /tmp/  134
perl-5.8.9      /tmp/    6
perl-5.8.8      /tmp/  134
perl-5.8.4      /tmp/  134
perl-5.6.2      /tmp/  134


Background:  I am doing co-maintenance on IPC-System-Simple and have 
released version 1.26 to CPAN.  The only test failure so far is on Linux 
with perl-5.8.9.  It turns out that the failure has nothing to do with 
the module's source code and can be replicated by the shell script I'm 

Thank you very much.
Jim Keenan

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