title: Manipulate Jenkins Job Parameter before using
body: <p>I wish to define a Jenkins build parameter, that would typically be entered by a user in a particular way.  In order to be used this parameter must be transformed by a simple function as follows (in shell script)</p>
  
  <pre><code>if [ "" != "${SUBPROJ}" ]
  then 
      CLEAN=`echo ":${SUBPROJ}:${CLEAN}" | sed 's|/|:|g' `
      END_TARGET=`echo ":${SUBPROJ}:${END_TARGET}" | sed 's|/|:|g' `
  fi  
  </code></pre>
  
  <p>This will convert something like a/b/c to :a:b:c:</p>
  
  <p>How in Jenkins can I do this conversion before the parameter is used.  Running a shell script step does not change the original parameter.  </p>
  
  <p>I looked at the <a href="https://wiki.jenkins-ci.org/display/JENKINS/Dynamic+Parameter+Plug-in" rel="nofollow noreferrer">dynamic parameter plugin</a> but that doesn't appear to allow for input from the supplied parameters</p>