http://www.perlmonks.org?node_id=988873


in reply to Problem with Parentheses

This avoids the error for me: 
my $cmd = 'find . -type f \( -perm -0020 -o -perm -0004 -o -perm -0002
+ -o -perm -0001 -o -perm -1000 \) -ls';
my $out = "output.txt";
open (MYFILE,"> $out");
print MYFILE `$cmd`;

[download]

See also:

In Section Seekers of Perl Wisdom