First of all, always run your code examples under "use strict" and "use warnings" -- they'll almost always give you hints when you don't get what you expect

On your first question, the first foreach is using "." (concatenate) instead of an assignment.

foreach (@step) {
  $step = $step . $_;  # or shorthand: $step .= $_
}
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If you ran your code with warnings, you'd get this message:

On your second question, it's a little garbled as to what you're trying to do. For one, you're not using regular expression delimiters:

$_ =~ /($what){3}/  # match things in $what 3 times
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Second, I'm not sure what you mean by "print three times", but the regex /(fred|barney){3}/ means to match any combination of "fred" or "barney" that appears three times in a row, e.g. "fredfredfred" or "fredbarneyfred" or any combination like that. I'm not sure that's what you intended.

Hope that helps