Exit on change option

src/Microsoft.Dnx.Watcher.Core/DnxWatcher.cs

@@ -19,6 +19,8 @@ namespace Microsoft.Dnx.Watcher.Core
 
         private readonly ILogger _logger;
 
+        public bool ExitOnChange { get; set; }
+
         public DnxWatcher(
             Func<string, IFileWatcher> fileWatcherFactory,
             Func<IProcessWatcher> processWatcherFactory,
@@ -88,6 +90,11 @@ namespace Microsoft.Dnx.Watcher.Core
                             _logger.LogError($"dnx exit code: {dnxExitCode}");
                         }
 
+                        if (ExitOnChange)
+                        {
+                            break;
+                        }
+
                         _logger.LogInformation("Waiting for a file to change before restarting dnx...");
                         // Now wait for a file to change before restarting dnx
                         await WaitForProjectFileToChangeAsync(project, cancellationToken);
@@ -97,6 +104,11 @@ namespace Microsoft.Dnx.Watcher.Core
                         // This is a file watcher task
                         string changedFile = fileWatchingTask.Result;
                         _logger.LogInformation($"File changed: {fileWatchingTask.Result}");
+
+                        if (ExitOnChange)
+                        {
+                            break;
+                        }
                     }
                 }
             }

src/Microsoft.Dnx.Watcher/Program.cs

@@ -77,10 +77,15 @@ namespace Microsoft.Dnx.Watcher
                 CommandOptionType.SingleValue);
 
             var workingDirArg = app.Option(
-                "--workingDir <DIR>",
+                "--working-dir <DIR>",
                 "The working directory for DNX. Defaults to the current directory.",
                 CommandOptionType.SingleValue);
 
+            var exitOnChangeArg = app.Option(
+                "--exit-on-change",
+                "The watcher will exit when a file change is detected instead of restarting the process.",
+                CommandOptionType.NoValue);
+
             // This option is here just to be displayed in help
             // it will not be parsed because it is removed before the code is executed
             app.Option(
@@ -104,6 +109,8 @@ namespace Microsoft.Dnx.Watcher
                     Directory.GetCurrentDirectory();
 
                 var watcher = DnxWatcher.CreateDefault(_loggerFactory);
+                watcher.ExitOnChange = exitOnChangeArg.HasValue();
+
                 try
                 {
                     watcher.WatchAsync(projectToRun, dnxArgs, workingDir, cancellationToken).Wait();