title: Jenkins variable to fetch SVN checkin number
body: <p>Gurus,</p>
  
  <p>I am using windows jenkins and linux SVN to build java code using maven.</p>
  
  <p>My requirements is to validate to proceed with build execution in jenkins job after verifying that is there no specific list of files are changed in latest triggered job.</p>
  
  <p>if specific file is present we should get promot to continue job.</p>
  
  <p>I know i can use command<br>
  <code>svn diff -r REV:HEAD --summarize | findstr /g:"filesname.list"</code></p>
  
  <p>how to get the last successful build SVN revision  and latest checked out revision from jenkins in script at run time ?</p>
  
  <p>Also how pre buld script in jenkins job provide me interface to give my goahead decison  to continue job?</p>