diff --git a/Jenkinsfile b/Jenkinsfile
index c00f695..a37aa7b 100644
--- a/Jenkinsfile
+++ b/Jenkinsfile
@@ -14,6 +14,10 @@ def sftp_host = ''
 def sftp_user = ''
 def sftp_passwd = ''
 def sftp_path = '/jenkins/owrt/'
+def isBuildNeeded = false
+def deleteUnbuild = true
+def pre_clean = true
+def post_clean = false
 
 
 if(params.DEBUG)
@@ -44,6 +48,18 @@ if(params.KNOWN_HOSTS)
 {
 	known_hosts = params.KNOWN_HOSTS
 }
+if(params.DeleteUnbuild)
+{
+	deleteUnbuild = params.DeleteUnbuild
+}
+if(params.PRE_CLEAN)
+{
+	pre_clean = params.PRE_CLEAN
+}
+if(params.POST_CLEAN)
+{
+	post_clean = params.POST_CLEAN
+}
 
 def printDebug(msg)
 {
@@ -55,44 +71,63 @@ def printDebug(msg)
 node('test')
 {
 	
-   stageName = 'checkout'
-   stage(stageName)
+   stage('checkout')
    {
-		cleanWs()
+		if(pre_clean)
+		{
+			cleanWs()
+		}
 		sh label: 'checkout_configs', script: 'git clone ' + script_git + ' ' + script_folder
 		sh label: 'checkout_openwrt', script: 'git clone ' + git_link + ' ' + git_folder
 		def ret = sh label: 'is_build_needed', script: 'python ' + scripts_path + 'sftp_test.py -a ' + sftp_host + ' -u ' + sftp_user + ' -p ' + sftp_passwd + ' -g ' + git_folder + ' -f ' + scripts_path + known_hosts + ' -l ' + sftp_path, returnStdout: true
-		printDebug(ret)
+		if(ret.trim().equalsIgnoreCase('True')
+			isBuildNeeded = true
 	}
 	return
 	
-	stageName = 'pre-build'
-	stage(stageName)
+	if(isBuildNeeded)
 	{
-		sh label: 'patch_sources', script: 'cd ' + git_folder + '; patch -p1 < ../' + patch
-		sh label: 'feeds_update', script: 'cd ' + git_folder + '; ./scripts/feeds update -a'
-		sh label: 'feeds_install', script: 'cd ' + git_folder + '; ./scripts/feeds install -a'
+		stage('pre-build')
+		{
+			sh label: 'patch_sources', script: 'cd ' + git_folder + '; patch -p1 < ../' + patch
+			sh label: 'feeds_update', script: 'cd ' + git_folder + '; ./scripts/feeds update -a'
+			sh label: 'feeds_install', script: 'cd ' + git_folder + '; ./scripts/feeds install -a'
 		
-	}
-    
-   stageName = 'build'
-   stage(stageName)
-   {
-		//step
-		//{
-		sh label: 'copy_config', script: 'cp ' + config_path + 'tl_wr841_v11_config ' + git_folder + '/.config'
-		sh label: 'build_v11', script: 'cd ' + git_folder + '; make oldconfig; make -j13 V=s'
-		//}
-		//step
-		//{
-		sh label: 'copy_config', script: 'cp ' + config_path + 'tl_wr841_v12_config ' + git_folder + '/.config'
-		sh label: 'build_v12', script: 'cd ' + git_folder + '; make oldconfig; make -j13 V=s'
-		//}
+		}
+		
+		stage('build')
+		{
+			//step
+			//{
+			sh label: 'copy_config', script: 'cp ' + config_path + 'tl_wr841_v11_config ' + git_folder + '/.config'
+			sh label: 'build_v11', script: 'cd ' + git_folder + '; make oldconfig; make -j13 V=s'
+			//}
+			//step
+			//{
+			sh label: 'copy_config', script: 'cp ' + config_path + 'tl_wr841_v12_config ' + git_folder + '/.config'
+			sh label: 'build_v12', script: 'cd ' + git_folder + '; make oldconfig; make -j13 V=s'
+			//}
+		}
    }
    
-   stageName = 'clean'
-   stage(stageName)
+   if(post_clean)
    {
-		//cleanWs()
+		stage('clean')
+		{
+			cleanWs()
+		}
 	}
+	
+	if((!isBuildNeeded && deleteUnbuild))
+   {
+      //if no build is needed, then the last build is deleted and the next build number is set to previous build number
+      
+      def jobName = JOB_NAME
+      def job = Jenkins.instance.getItem(jobName)
+      logger.printInfo('job is getting deleted ' + currentBuild.id.toString())//job.nextBuildNumber)
+      job.getLastBuild().delete()
+      //job.nextBuildNumber -= 1 //updateNextBuildNumber(job.getNextBuildNumber() - 1)      //resetting next build number does not work. if done, the next build start will do nothing
+      job.save()
+   }
+	
 }