my $CF = new FileHandle "$cntrF", O_RDWR | O_APPEND || die '"cntrF' di
+d not open $!\n";
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Because of the relatively high precedence of the || operator that expression is interpreted as:

my $CF = new FileHandle $cntrF, ( O_RDWR | O_APPEND || die "'cntrF' di
+d not open $!\n" );
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You need to either use parentheses:

( my $CF = new FileHandle $cntrF, O_RDWR | O_APPEND ) || die "'cntrF' 
+did not open $!\n";
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Or use the lower precedence "or" operator:

my $CF = new FileHandle $cntrF, O_RDWR | O_APPEND or die "'cntrF' did 
+not open $!\n";
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