diff --git a/src/main/kotlin/org/domaindrivenarchitecture/provs/desktop/application/Application.kt b/src/main/kotlin/org/domaindrivenarchitecture/provs/desktop/application/Application.kt
index b08f513..6f40e37 100644
--- a/src/main/kotlin/org/domaindrivenarchitecture/provs/desktop/application/Application.kt
+++ b/src/main/kotlin/org/domaindrivenarchitecture/provs/desktop/application/Application.kt
@@ -38,8 +38,8 @@ fun main(args: Array<String>) {
             null
         } catch (e: FileNotFoundException) {
             println(
-                "Error: File\u001b[31m ${configFileName} \u001b[0m was not found.\n" +
-                        "Pls copy file \u001B[31m desktop-config-example.yaml \u001B[0m to file \u001B[31m ${configFileName} \u001B[0m " +
+                "Error: File\u001b[31m $configFileName \u001b[0m was not found.\n" +
+                        "Pls copy file \u001B[31m desktop-config-example.yaml \u001B[0m to file \u001B[31m $configFileName \u001B[0m " +
                         "and change the content according to your needs."
             )
             null
diff --git a/src/main/kotlin/org/domaindrivenarchitecture/provs/framework/core/docker/HostDocker.kt b/src/main/kotlin/org/domaindrivenarchitecture/provs/framework/core/docker/HostDocker.kt
index 460a1df..9bc449e 100644
--- a/src/main/kotlin/org/domaindrivenarchitecture/provs/framework/core/docker/HostDocker.kt
+++ b/src/main/kotlin/org/domaindrivenarchitecture/provs/framework/core/docker/HostDocker.kt
@@ -6,7 +6,7 @@ import org.domaindrivenarchitecture.provs.framework.core.docker.dockerimages.Doc
 import org.domaindrivenarchitecture.provs.framework.core.docker.platforms.*
 import org.domaindrivenarchitecture.provs.framework.core.platforms.UbuntuProv
 import org.domaindrivenarchitecture.provs.framework.core.processors.ContainerStartMode
-import org.domaindrivenarchitecture.provs.framework.core.docker.platforms.*
+
 
 private const val DOCKER_NOT_SUPPORTED = "docker not yet supported for "
 
@@ -17,7 +17,7 @@ fun Prov.dockerProvideImage(image: DockerImage, skipIfExisting: Boolean = true,
     if (this is UbuntuProv) {
         return this.dockerProvideImagePlatform(image, skipIfExisting, sudo)
     } else {
-        throw RuntimeException(DOCKER_NOT_SUPPORTED + (this as UbuntuProv).javaClass)
+        throw RuntimeException(DOCKER_NOT_SUPPORTED + this.javaClass)
     }
 }
 
@@ -28,7 +28,7 @@ fun Prov.dockerImageExists(imageName: String, sudo: Boolean = true) : Boolean {
     if (this is UbuntuProv) {
         return this.dockerImageExistsPlatform(imageName, sudo)
     } else {
-        throw RuntimeException(DOCKER_NOT_SUPPORTED + (this as UbuntuProv).javaClass)
+        throw RuntimeException(DOCKER_NOT_SUPPORTED + this.javaClass)
     }
 }
 
@@ -50,7 +50,7 @@ fun Prov.provideContainer(
     if (this is UbuntuProv) {
         return this.provideContainerPlatform(containerName, imageName, startMode, sudo, options, command)
     } else {
-        throw RuntimeException(DOCKER_NOT_SUPPORTED + (this as UbuntuProv).javaClass)
+        throw RuntimeException(DOCKER_NOT_SUPPORTED + this.javaClass)
     }
 }
 
@@ -59,7 +59,7 @@ fun Prov.containerRuns(containerName: String, sudo: Boolean = true) : Boolean {
     if (this is UbuntuProv) {
         return this.containerRunsPlatform(containerName, sudo)
     } else {
-        throw RuntimeException(DOCKER_NOT_SUPPORTED + (this as UbuntuProv).javaClass)
+        throw RuntimeException(DOCKER_NOT_SUPPORTED + this.javaClass)
     }
 }
 
@@ -72,7 +72,7 @@ fun Prov.runContainer(
     if (this is UbuntuProv) {
         return this.runContainerPlatform(containerName, imageName, sudo)
     } else {
-        throw RuntimeException(DOCKER_NOT_SUPPORTED + (this as UbuntuProv).javaClass)
+        throw RuntimeException(DOCKER_NOT_SUPPORTED + this.javaClass)
     }
 }
 
@@ -84,16 +84,17 @@ fun Prov.exitAndRmContainer(
     if (this is UbuntuProv) {
         return this.exitAndRmContainerPlatform(containerName, sudo)
     } else {
-        throw RuntimeException(DOCKER_NOT_SUPPORTED + (this as UbuntuProv).javaClass)
+        throw RuntimeException(DOCKER_NOT_SUPPORTED + this.javaClass)
     }
 }
 
 
+@Suppress("unused")
 fun Prov.containerExec(containerName: String, cmd: String, sudo: Boolean = true): ProvResult {
     if (this is UbuntuProv) {
         return this.containerExecPlatform(containerName, cmd, sudo)
     } else {
-        throw RuntimeException(DOCKER_NOT_SUPPORTED + (this as UbuntuProv).javaClass)
+        throw RuntimeException(DOCKER_NOT_SUPPORTED + this.javaClass)
     }
 }
 
diff --git a/src/main/kotlin/org/domaindrivenarchitecture/provs/framework/core/platforms/UbuntuProv.kt b/src/main/kotlin/org/domaindrivenarchitecture/provs/framework/core/platforms/UbuntuProv.kt
index f2c8791..97eacc6 100644
--- a/src/main/kotlin/org/domaindrivenarchitecture/provs/framework/core/platforms/UbuntuProv.kt
+++ b/src/main/kotlin/org/domaindrivenarchitecture/provs/framework/core/platforms/UbuntuProv.kt
@@ -30,13 +30,15 @@ open class UbuntuProv(
     }
 
     private fun buildCommand(vararg args: String): String {
-        return if (args.size == 1)
+        return if (args.size == 1) {
             args[0].escapeAndEncloseByDoubleQuoteForShell()
-        else
-            if (args.size == 3 && SHELL.equals(args[0]) && "-c".equals(args[1]))
+        } else {
+            if (args.size == 3 && SHELL == args[0] && "-c" == args[1]) {
                 SHELL + " -c " + args[2].escapeAndEncloseByDoubleQuoteForShell()
-            else
+            } else {
                 args.joinToString(separator = " ")
+            }
+        }
     }
 }
 
diff --git a/src/main/kotlin/org/domaindrivenarchitecture/provs/framework/ubuntu/filesystem/base/Filesystem.kt b/src/main/kotlin/org/domaindrivenarchitecture/provs/framework/ubuntu/filesystem/base/Filesystem.kt
index 28dcb9e..8cf4415 100644
--- a/src/main/kotlin/org/domaindrivenarchitecture/provs/framework/ubuntu/filesystem/base/Filesystem.kt
+++ b/src/main/kotlin/org/domaindrivenarchitecture/provs/framework/ubuntu/filesystem/base/Filesystem.kt
@@ -201,7 +201,7 @@ fun Prov.fileContentLargeFile(file: String, sudo: Boolean = false, chunkSize: In
         // check first chunk
         if (resultString == null) {
             if (!chunkResult.success) {
-                return resultString
+                return null
             } else {
                 resultString = ""
             }
diff --git a/src/main/kotlin/org/domaindrivenarchitecture/provs/framework/ubuntu/secret/SecretSource.kt b/src/main/kotlin/org/domaindrivenarchitecture/provs/framework/ubuntu/secret/SecretSource.kt
index a48d973..ae979ef 100644
--- a/src/main/kotlin/org/domaindrivenarchitecture/provs/framework/ubuntu/secret/SecretSource.kt
+++ b/src/main/kotlin/org/domaindrivenarchitecture/provs/framework/ubuntu/secret/SecretSource.kt
@@ -13,7 +13,7 @@ abstract class SecretSource(protected val input: String) {
 
 
 @Serializable
-enum class SecretSourceType() {
+enum class SecretSourceType {
 
     PLAIN, FILE, PROMPT, PASS, GOPASS;
 
diff --git a/src/test/kotlin/org/domaindrivenarchitecture/provs/server/infrastructure/K3sKtTest.kt b/src/test/kotlin/org/domaindrivenarchitecture/provs/server/infrastructure/K3sKtTest.kt
index 60405a1..3ca6837 100644
--- a/src/test/kotlin/org/domaindrivenarchitecture/provs/server/infrastructure/K3sKtTest.kt
+++ b/src/test/kotlin/org/domaindrivenarchitecture/provs/server/infrastructure/K3sKtTest.kt
@@ -1,11 +1,7 @@
 package org.domaindrivenarchitecture.provs.server.infrastructure
 
-import org.domaindrivenarchitecture.provs.framework.core.Secret
 import org.domaindrivenarchitecture.provs.framework.core.local
 import org.domaindrivenarchitecture.provs.framework.core.remote
-import org.domaindrivenarchitecture.provs.framework.ubuntu.filesystem.base.createDir
-import org.domaindrivenarchitecture.provs.framework.ubuntu.filesystem.base.createSecretFile
-import org.domaindrivenarchitecture.provs.framework.ubuntu.secret.secretSources.PromptSecretSource
 import org.domaindrivenarchitecture.provs.server.domain.k3s.K3sConfig
 import org.domaindrivenarchitecture.provs.server.domain.k3s.Node
 import org.domaindrivenarchitecture.provs.server.domain.k3s.provisionK3s
@@ -14,6 +10,7 @@ import org.junit.jupiter.api.Disabled
 import org.junit.jupiter.api.Test
 import java.lang.Thread.sleep
 
+
 class K3sKtTest {
 
     @Test   // Extensive test, takes several minutes