diff --git a/youtube_dl/postprocessor/execafterdownload.py b/youtube_dl/postprocessor/execafterdownload.py
index 24af1d916..08292e123 100644
--- a/youtube_dl/postprocessor/execafterdownload.py
+++ b/youtube_dl/postprocessor/execafterdownload.py
@@ -18,14 +18,16 @@ class ExecAfterDownloadPP(PostProcessor):
 
     def run(self, information):
         cmd = self.exec_cmd
-
-        # expose info to exec argument
-        # youtube-dl -x -o "%(playlist_index)s - %(title)s.%(ext)s" --exec "id3v2 -T %(playlist_index)s -t %(title)s %(filepath)s" PLAYLIST_ID
         str_types = (str) if sys.version_info.major > 2 else (str, unicode)
         info = {}
+
+        if '%(filepath)s' not in cmd:
+            cmd += ' %(filepath)s'
+
         for key in information:
             value = information[key]
             info[key] = compat_shlex_quote(value) if isinstance(value, str_types) else value
+
         cmd = cmd % info
 
         self._downloader.to_screen('[exec] Executing command: %s' % cmd)