diff --git a/hentai/cmdline.py b/hentai/cmdline.py
index b197e4a..957e02c 100644
--- a/hentai/cmdline.py
+++ b/hentai/cmdline.py
@@ -16,6 +16,7 @@ def banner():
 def cmd_parser():
     parser = OptionParser()
     parser.add_option('--search', type='string', dest='keyword', action='store', help='keyword searched')
+    parser.add_option('--tag', type='string', dest='tag', action='store', help='dojinshi tag')
     parser.add_option('--download', dest='is_download', action='store_true', help='download dojinshi or not')
     parser.add_option('--id', type='int', dest='id', action='store', help='dojinshi id of nhentai')
     parser.add_option('--ids', type='str', dest='ids', action='store', help='dojinshi id set, e.g. 1,2,3')
@@ -34,13 +35,13 @@ def cmd_parser():
         parser.print_help()
         raise SystemExit
 
-    if args.keyword:
-        logger.critical(u'并没有做这个功能_(:3」∠)_')
-        raise SystemExit
-
     if args.id:
         args.ids = (args.id, ) if not args.ids else args.ids
 
+    if args.tag:
+        logger.critical(u'并没有做这个功能_(:3」∠)_')
+        raise SystemExit
+
     if not args.keyword and not args.ids:
         parser.print_help()
         raise SystemExit
diff --git a/hentai/parser.py b/hentai/parser.py
index f4cf2e5..1224a70 100644
--- a/hentai/parser.py
+++ b/hentai/parser.py
@@ -48,7 +48,12 @@ def dojinshi_parser(id):
     return dojinshi
 
 
-def search_parser(data):
+def search_parser(keyword):
+    logger.debug('Searching dojinshis of keyword %s' % keyword)
+    return []
+
+
+def tag_parser(tag):
     pass
 
 
diff --git a/nhentai.py b/nhentai.py
index 0fefc1b..55d4bdb 100644
--- a/nhentai.py
+++ b/nhentai.py
@@ -1,6 +1,6 @@
 #coding: utf-8
 from hentai.cmdline import cmd_parser, banner
-from hentai.parser import dojinshi_parser
+from hentai.parser import dojinshi_parser, search_parser
 from hentai.dojinshi import Dojinshi
 from hentai.downloader import Downloader
 from hentai.logger import logger
@@ -16,13 +16,18 @@ def main():
     logger.log(15, 'nHentai: あなたも変態。 いいね?')
 
     dojinshi_list = []
-    if options.ids:
-        for id in options.ids:
+
+    if options.keyword:
+        dojinshi_ids = search_parser(options.keyword)
+    else:
+        dojinshi_ids = options.ids
+
+    if dojinshi_ids:
+        for id in dojinshi_ids:
             dojinshi_info = dojinshi_parser(id)
             dojinshi_list.append(Dojinshi(**dojinshi_info))
-    elif options.keyword:
-        pass
     else:
+        logger.log(15, 'Nothing has been done.')
         raise SystemExit
 
     if options.is_download: