how to concatenate strings in a Jenkinsfile?
<p>I'm trying to concatenate some strings in a Jenkinsfile but it's not working:</p>

<pre><code>def versionFromFile = readFile("./version")
def version = versionFromFile + env.BUILD_NUMBER
</code></pre>

<p>I tried other solutions as well:</p>

<pre><code>sh "echo version: ${version}-${env.BUILD_NUMBER}"
sh "git tag ${version}-${env.BUILD_NUMBER}"
</code></pre>

<p>but ${env.BUILD_NUMBER} is not evaluated/printed</p>

<p>if I do</p>

<pre><code>sh "git tag 1.0.1-${env.BUILD_NUMBER}"
</code></pre>

<p>${env.BUILD_NUMBER} is evaluated/printed</p>

<p>I still don't get how the scripting language works inside the Jenkinsfile, the documentation is all about the DSL, does that means that you can't do common scripting operations?</p>