The difference between system("mkdir -p $foo") and system mkdir => -p => $foo; is more than just the style of commas. Single argument system is subject to shell interpretation, while multi argument system is not.

Having said that, I tend to use => to separate arguments which have totally different roles - most often to separate the first argument from the rest:

    push @array => 1, 2, 3, 4;
    printf "%s %6d %s" => $foo, $bar, $baz;
    pack "C" => $var;
    splice @array => 0, 3 => "foo", "bar", "baz";
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Etc. I've used that long before people started preaching that => was some kind of pair creator. It never was, and still isn't. And I'm not the only one using this style, Larry Rosler (of GRT fame) was a vivid user of this style as well.

Abigail