Add handling for multiple processes on a part

- With the currently process filtering, if multiple processes are returned as running on port 3000, this command would fail. This splits apart the process IDing and the process naming, to support multiple processes.
- One curious thing about the bash command to get processes, is that it'll include browsers with a window open on localhost:3000. May want to reconsider that.

Author: Ian McNally

packages/react-scripts/scripts/start.js

@@ -260,11 +260,18 @@ function run(port) {
 }
 
 function getProcessNameOnPort(port) {
-  var command = 'ps -o command -p "$(lsof -i:' + port + ' -P -t)" | sed -n 2p | tr -d "\n"';
   var execOptions = { encoding: 'utf8' };
+  var processesCommand = 'lsof -i:' + port + ' -P -t'
 
   try {
-    return execSync(command, execOptions);
+    var processIds = execSync(processesCommand, execOptions).match(/(\S+)/g);
+
+    var namedProcesses = processIds.map(function(processId) {
+      var command = 'ps -o command -p ' + processId + ' | sed -n 2p | tr -d "\n"';
+      return execSync(command, execOptions);
+    });
+
+    return namedProcesses.join(',\n  ');
   } catch(e) {
     return null;
   }