Am trying to understand why both of these variations take the same time to execute/complete...

The first piece of code runs a shell grep and writes the output into a file. The contents of the file is then read into a array using perl. 

qx{cut -d"," -f17 $file | sort | uniq > $tmpfile};
open my $fh1, "<:encoding(utf-8)","$tmpfile" or die "$tmpfile: $!";
while (<$fh1>) {
    chomp;
    push @names, split (/\n/);
}
$fh1->close;

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The second piece of code is way more easier to write and feels more direct (i.e., pass the output of the shell grep to an array - job done! However, this takes the same amount of time as the previous piece (time measured in seconds). I'd have thought that writing to a file and reading it back would have slowed me down, but it didn't! I'm currently running over a fairly small'ish set of data ($file = approx.100Mb, and $tmpfile = 50Kb). Is there a bias towards either of these approaches (driven by performance) should the dataset get significantly larger? 

my @names = qx{cut -d"," -f17 $file | sort | uniq};

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In reply to search/grep perl/*nix by Gtforce

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