#!/usr/bin/perl

use strict;
use warnings;

use File::Copy qw( copy );

copy $ARGV[0], $ARGV[1];
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It needs error checking.

If you need to hardcode a UNC path, you can either properly escape backslashes

my $path = '\\\\server\\share\\dir\\file';
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or simply use forward slashes.

my $path = '//server/share/dir/file';
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open has no problem with either.