diff --git a/monitordisplay b/monitordisplay
index 96b5269..7c87168 100755
--- a/monitordisplay
+++ b/monitordisplay
@@ -46,6 +46,8 @@ function filterMode(array $data)
     $default = [
         'config' => [],
         'primary' => null,
+        'before_command' => null,
+        'after_command' => null,
     ];
 
     $data = filter($data, $default);
@@ -107,7 +109,7 @@ function build(array $modes, array $screens, $mode, $toggle, array $currentMode,
         if ($currentMode['config'] === null) {
             return;
         }
-        
+
         $configs = $mode['config'];
         $configsKeys = array_keys($configs);
 
@@ -117,7 +119,7 @@ function build(array $modes, array $screens, $mode, $toggle, array $currentMode,
 
         if ($toggle === true) {
             foreach ($configsKeys as $k => $key) {
-                if ($key === $currentMode['config']) {
+                if ($key == $currentMode['config']) {
                     $currentKey = $k;
                 }
             }
@@ -130,7 +132,7 @@ function build(array $modes, array $screens, $mode, $toggle, array $currentMode,
             die(1);
         }
     } else {
-        $config = 0;
+        $config = array_keys($mode['config'])[0];
     }
 
     if (!array_key_exists($config, $mode['config'])) {
@@ -162,7 +164,7 @@ function build(array $modes, array $screens, $mode, $toggle, array $currentMode,
         }
 
         $command[] = '--output';
-        $command[] = $name;
+        $command[] = escapeshellarg($name);
         $screensUsed[] = $name;
 
         if ($mode['primary'] === $name) {
@@ -174,14 +176,14 @@ function build(array $modes, array $screens, $mode, $toggle, array $currentMode,
 
         $command[] = '--pos';
         $command[] = sprintf('%dx%d', $x, 0);
-        $x += $resolutionX;
+        $x += (int) $resolutionX;
     }
 
     if ($addOff) {
         foreach ($screens as $screen) {
             if (!in_array($screen['name'], $screensUsed)) {
                 $command[] = '--output';
-                $command[] = $screen['name'];
+                $command[] = escapeshellarg($screen['name']);
                 $command[] = '--off';
             }
         }
@@ -192,6 +194,7 @@ function build(array $modes, array $screens, $mode, $toggle, array $currentMode,
     return [
         'config' => sprintf("mode=%s\nconfig=%s", $tmpMode, $tmpConfig),
         'command' => $command,
+        'mode' => $mode,
     ];
 }
 
@@ -209,7 +212,7 @@ foreach ($files as $file) {
         $parsing = @parse_ini_file($file, true);
 
         if ($parsing === false) {
-            error(sprintf('The file "%s" is not a valid ini file.', $file));
+            error(sprintf('The file "%s" is not a valid ini file', $file));
 
             continue;
         }
@@ -225,7 +228,7 @@ foreach ($files as $file) {
 
 if (empty($config)) {
     error('No configuration found');
-    error(sprintf('Paths checked: %s', implode(', ', $files)));
+    error(sprintf('Paths checked: \n%s', implode(', ', $files)));
     die(1);
 }
 
@@ -236,7 +239,7 @@ foreach ($config as $section => $values) {
     $type = explode(':', $section);
 
     if (count($type) !== 2) {
-        error(sprintf('Invalid section "%s". Ignored.', $section));
+        error(sprintf('Invalid section "%s". Ignored', $section));
     }
 
     if ($type[0] === 'screen') {
@@ -244,17 +247,17 @@ foreach ($config as $section => $values) {
     } elseif ($type[0] === 'mode') {
         $modes[$type[1]] = filterMode($values);
     } else {
-        error(sprintf('Invalid section "%s". Ignored.', $section));
+        error(sprintf('Section "%s" ignored', $section));
     }
 }
 
 if (empty($screens)) {
-    error('No screen found.');
+    error('No screen found');
     die(1);
 }
 
 if (empty($modes)) {
-    error('No mode found.');
+    error('No mode found');
     die(1);
 }
 
@@ -266,5 +269,26 @@ $build = build($modes, $screens, $mode, $toggle, $currentMode, $addOff);
 
 if (!empty($build)) {
     file_put_contents(getCurrentModeFile(), $build['config']);
-    shell_exec($build['command']);
+
+    $commands = [
+        $build['mode']['before_command'],
+        $build['command'],
+        $build['mode']['after_command']
+    ];
+
+    $output = [];
+
+    foreach ($commands as $command) {
+        if (!empty($command)) {
+            $output[] = 'Command: '.$command;
+            exec($command, $output);
+        }
+    }
+
+    notice(implode("\n", $output));
+
+    die(0);
 }
+
+error(sprintf('Invalid mode "%s"', $mode));
+die(1);