I read your reply below. It is an error I have never encountered myself but it does look like the issue:

for ( qw( This is new to me ) ) {
    print "$_\n";
    open(PIPE, "dir|") or die $!;
    while (<PIPE>) { # <--- This is the line that the error points to
        print $_; 
    }
}
__DATA__
This
Modification of a read-only value attempted at script line 4.
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Learn something every day. Thanks!