How about 
use File::Copy qw(move);

my $extension = "12345";
move("file", "file.$extension");

[download]
There's also the handy rename() function, but is known to have various platform issues. See the File::Copy docs for more info.
HTH

_________
broquaint

In reply to Re: Insert extension to filename by broquaint
in thread Insert extension to filename by rchou2

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