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What's the proper way to define optional attributes in a define in puppet? Right now I'm doing this:

define($command = "none") {

and then things like (in a template):

<% if command != "none" %>
do something with <%= command %>
<% end %>

Is there a more proper way to define optional attributes? Something more akin to nil or null instead of "none"?

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up vote 3 down vote accepted

You can use undef. In the define you use it explicitly, like:

define($command = undef) {

while in templates, undef variables won't get instance variables define, so they'll be nil:

<% if @command %>
do something with <%= @command %>
<% end %>
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