First 'attach' mode, works fine

main.js

@@ -13,17 +13,53 @@ var client; /* Sub process for the express server */
 
 class Lektor {
     constructor() {
-        this.closed = false;
-        this.process = spawn('lektord', ['-F']);
+        this.closed = true;
 
-        this.process.stderr.on('data', data => {
-            logger.lektord(data);
+        this.isRunning('lektord.exe', 'lektord', 'lektord').then(v => {
+            if (v && config.attachmode) {
+                logger.info('main', `Lektord is running! Attach to it`);
+            } else if (v) {
+                logger.error('error', `Lektord is running and attach mode is disable, exit!`);
+                app.quit();
+            } else {
+                logger.debug('main', `Lektord not running, start it!`);
+                this.closed = false;
+                this.process = spawn('lektord', ['-F']);
+
+                this.process.stderr.on('data', data => {
+                    logger.lektord(data);
+                });
+
+                this.process.on('close', code => {
+                    logger.warn('main', `Lektor exited with code ${code}`);
+                    this.lektor_closed = true;
+                    app.quit();
+                });
+            }
         });
+    }
 
-        this.process.on('close', code => {
-            logger.warn('main', `Lektor exited with code ${code}`);
-            this.lektor_closed = true;
-            app.quit();
+    isRunning(win, mac, linux) {
+        return new Promise(function (resolve, reject) {
+            //var ps = require('ps-node');
+            const exec = require('child_process').exec;
+
+            const plat = process.platform;
+            const cmd =
+                plat == 'win32'
+                    ? 'tasklist'
+                    : plat == 'darwin'
+                    ? 'ps -ax | grep ' + mac
+                    : plat == 'linux'
+                    ? 'ps -A'
+                    : '';
+            const proc = plat == 'win32' ? win : plat == 'darwin' ? mac : plat == 'linux' ? linux : '';
+            if (cmd === '' || proc === '') {
+                resolve(false);
+            }
+            exec(cmd, function (err, stdout, stderr) {
+                resolve(stdout.toLowerCase().indexOf(proc.toLowerCase()) > -1);
+            });
         });
     }