Hi Koda1234,

The preferred (because it's safest ) way to open a file is the "three-argument form" (see open [suggestion: as a beginner, read the docs for the various functions; don't just copy examples you may see in the wild ]).

Also:

• Check that you got any input before using it.
• $! will report the cause of open die-ing, but you can make your own check of the file so you can use your own error message.
• Use while to read from your filehandle one line at a time, so even if it's big it won't fill your memory.
• Use chomp to trim the newline character off the end of the line. Doesn't matter in your example, but it will soon enough...
• Declare your array outside the while loop and use push to add the values to it as you split the lines.

use strict; use warnings; use feature 'say';

my $filename = $ARGV[0] or die "You must supply a filename";
-f $filename or die "You must supply the name of a file that exists!";

open my $IN, '<', $filename or die "Can't open < $filename: $!";

my @col9;

while ( my $line = <$IN> ) {
    chomp $line;
    push @col9, (split / /, $line)[8];
}

close $IN or die "Can't close $filename: $!";

foreach my $test ( 1, 9, 42, 666 ) {
    my $count = scalar grep { $_ >= $test } @col9;
    say sprintf "%d values were >= %d", $count, $test;
}

__END__
[download]

Hope this helps!