The simple.t failed because of an insecure $ENV{PATH} when running under -T. -T stands for "enable tainting checks". Perl goes into paranoid mode and obsessively/compulsively does run-time checking of all the paths of execution that the script could take; hence it's looking at all the paths and not getting any. You'll need to set $ENV{PATH} something like this in your script:

$ENV{'PATH'} = '/bin:/usr/bin';
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Or in your terminal:

export PATH=/bin:/usr/bin
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Update: corrected