You could define it as an anonymous subroutine and store it in a code ref:

$subref=eval 'sub { your code here }'
die $@ if $@;
...
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And then call it any time you want as:

$subref->();
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or define it like a normal subroutine:

eval 'sub mysub { your code here }';
die $@ if $@;
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And then call it with:

mysub();
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--ZZamboni