#!/bin/perl
use v5.14;
use warnings;
use Path::Tiny;
my $in = $ARGV[0] or die "Usage: $0 <filename>";

path($in)->copy($in =~ s/(\.\w+)?$/.out/r);

__END__

##</code><code>##

#!/bin/perl
use v5.14;
use warnings;
use Path::Tiny;
my $in = $ARGV[0] or die "Usage: $0 <filename>";

my $out = path($in =~ s/(\.\w+)?$/.out/r);

for my $line ( path($in)->lines({ chomp => 1 }) {
    # do something interesting with the line
    $out->append("$line\n");
}
__END__