#!/usr/bin/perl
$| = 1;
open(OUT, ">foo");
&CloseAllOpenFiles();
print "done with close.\n";
sleep 20;
# go look at process with lsof to see if fd still open

sub CloseAllOpenFiles
{ 
        local *F; 
        for (my $fd=0; $fd<=1024; $fd++)
        {
        open F, "<&=$fd" or warn "Cannot reopen fd=$fd: $!";
        close F;
        }
}