--gc.

modules/kobalt-plugin-api/src/main/kotlin/com/beust/kobalt/Args.kt

@@ -26,6 +26,9 @@ class Args {
             "actually running them")
     var dryRun: Boolean = false
 
+    @Parameter(names = arrayOf("--gc"), description = "Delete old files")
+    var gc: Boolean = false
+
     @Parameter(names = arrayOf("--help", "--usage"), description = "Display the help")
     var usage: Boolean = false
 

modules/kobalt-plugin-api/src/main/kotlin/com/beust/kobalt/misc/Io.kt

@@ -0,0 +1,68 @@
+package com.beust.kobalt.misc
+
+import java.io.File
+import java.nio.file.Files
+import java.nio.file.Paths
+import java.nio.file.StandardCopyOption
+
+class Io(val dryRun: Boolean = false) {
+    fun mkdirs(dir: String) {
+        log("mkdirs $dir")
+        if (! dryRun) {
+            File(dir).mkdirs()
+        }
+    }
+
+    fun rm(path: String) {
+        log("rm $path")
+
+        if (! dryRun) {
+            File(path).deleteRecursively()
+        }
+    }
+
+    fun moveFile(from: File, toDir: File) {
+        log("mv $from $toDir")
+        if (! dryRun) {
+            require(from.exists(), { -> "$from should exist" })
+            require(from.isFile, { -> "$from should be a file" })
+            require(toDir.isDirectory, { -> "$toDir should be a file"})
+
+            val toFile = File(toDir, from.name)
+            Files.move(Paths.get(from.absolutePath), Paths.get(toFile.absolutePath), StandardCopyOption.ATOMIC_MOVE)
+        }
+    }
+
+    fun copyDirectory(from: File, toDir: File) {
+        log("cp -r $from $toDir")
+
+        if (! dryRun) {
+            KFiles.copyRecursively(from, toDir)
+            require(from.exists(), { -> "$from should exist" })
+            require(from.isDirectory, { -> println("$from should be a directory")})
+            require(toDir.isDirectory, { -> println("$toDir should be a file")})
+
+        }
+    }
+
+    fun rmDir(dir: File) {
+        log("rm -rf $dir")
+
+        if (! dryRun) {
+            require(dir.isDirectory,  { -> println("$dir should be a directory")})
+            dir.deleteRecursively()
+        }
+    }
+
+    fun mkdir(dir: File) {
+        log("rm -rf $dir")
+        if (! dryRun) {
+            dir.mkdirs()
+        }
+    }
+
+    private fun log(s: String) {
+        log(1, "[Io] $s")
+    }
+
+}