Use command -v for checking for programs

src/Chardet.php

@@ -15,11 +15,12 @@ class Chardet {
         foreach ($this->executables as $executable) {
             if (Util::commandExists($executable)) {
                 $this->executable = $executable;
+                break;
             }
         }
 
         if ($this->executable === null) {
-            throw new \RuntimeException('Chardet not installed');
+            throw new \RuntimeException('chardet not installed');
         }
     }
 

src/Util.php

@@ -4,8 +4,10 @@ namespace OrpheusNET\Logchecker;
 
 class Util {
     public static function commandExists($cmd) {
-        $return = shell_exec(sprintf("which %s", escapeshellarg($cmd)));
-        return !empty($return);
+        $where = substr(strtolower(PHP_OS), 0, 3) === 'win' ? 'where' : 'command -v';
+
+        exec("{$where} {$cmd} 2>/dev/null", $output, $return_var);
+        return $return_var === 0;
     }
 
     public static function strposArray(string $haystack, array $needles) {