my $genfile = 'c:\bemisia_coi.gb';

I know that your specification is technically correct, but since the OP is new to Perl and programming, I think it would be better to escape the backslash, though it's not strictly necessary here:

my $genfile = 'c:\\bemisia_coi.gb';
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Getting the habit of escaping backslashes inside single quotes every time, prevents from surprises when we one day have to write strings which are supposed to contain two backslashes in a row (such as UNC pathes on Windows):

# Access UNC path \\myserver\c$\Data
$genfile = '\\myserver\c$\Data\x.gb'; # wrong
$genfile = '\\\myserver\c$\Data\x.gb'; # correct, but doesn't look nic
+e
$genfile = '\\\\myserver\\c$\\Data\\x.gb'; # correct, and looks consis
+tent
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