$ ls -l input.txt
ls: input.txt: No such file or directory

$ perl -e '$input = q{input.txt}; @output = system ("ls -l >> input.txt");'

$ ls -l input.txt
-rw-r--r--  1 ken  staff  16393 12 Mar 15:34 input.txt

##</code><code>##

$ perl -e '
    use strict;
    use warnings;
    use autodie qw{:all};

    my $output_file = q{output.txt};
    my $return_value = system "ls -l >> $output_file";
'