You have to use a global variable of an open file: 
my $file;
open $file, ">$filename" || die("Couldn't open file");
...

[download]

In addition, are you assured that at this time there is data on the socket for reading?

In reply to Re: Close a file and reopen a new one at midnight by 0day
in thread Close a file and reopen a new one at midnight by Anonymous Monk

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