How to do it…

This is one example of using a regular expression in a conditional statement:

How it works…

Puppet treats the text supplied between the forward slashes as a regular expression specifying the text to be matched. If the match succeeds, the if expression will be true and so the code between the first set of curly braces will be executed.

If you wanted instead to do something if the text does not match, use !~ rather than =~:

if $::lsbdistdescription !~ /LTS/ {

There's more…

Regular expressions are very powerful, but can be difficult to understand and debug. If you find yourself using a regular expression so complex that you can't see at a glance what it does, think about simplifying your design to make it easier. However, one particularly useful feature of regular expressions is the ability to capture patterns.

$input = 'Puppet is better than manual configuration'
if $input =~ /(.*) is better than (.*)/ {
  notify { "You said '${0}'. Looks like you're comparing ${1}
    to ${2}!": }
}

You said 'Puppet is better than manual configuration'. Looks
like you're comparing Puppet to manual configuration!

See also