diff --git a/nhentai/cmdline.py b/nhentai/cmdline.py
index 02c54da..19c3e9d 100644
--- a/nhentai/cmdline.py
+++ b/nhentai/cmdline.py
@@ -23,10 +23,12 @@ def banner():
 def cmd_parser():
     parser = OptionParser()
     parser.add_option('--download', dest='is_download', action='store_true', help='download doujinshi or not')
+    parser.add_option('--show-info', dest='is_show', action='store_true', help='just show the doujinshi information.')
     parser.add_option('--id', type='str', dest='id', action='store', help='doujinshi ids set, e.g. 1,2,3')
-    parser.add_option('--search', type='string', dest='keyword', action='store', help='keyword searched')
+    parser.add_option('--search', type='string', dest='keyword', action='store', help='search doujinshi by keyword')
     parser.add_option('--page', type='int', dest='page', action='store', default=1,
                       help='page number of search result')
+    parser.add_option('--tags', type='string', dest='tags', action='store', help='download doujinshi by tags')
     parser.add_option('--output', type='string', dest='output_dir', action='store', default='',
                       help='output dir')
     parser.add_option('--threads', '-t', type='int', dest='threads', action='store', default=5,
@@ -37,11 +39,15 @@ def cmd_parser():
                       help='use proxy, example: http://127.0.0.1:1080')
     args, _ = parser.parse_args()
 
+    if args.tags:
+        logger.warning('`--tags` is under construction')
+        exit(0)
+
     if args.id:
         _ = map(lambda id: id.strip(), args.id.split(','))
         args.id = set(map(int, filter(lambda id: id.isdigit(), _)))
 
-    if args.is_download and not args.id and not args.keyword:
+    if (args.is_download or args.is_show) and not args.id and not args.keyword:
         logger.critical('Doujinshi id(s) are required for downloading')
         parser.print_help()
         exit(0)
diff --git a/nhentai/command.py b/nhentai/command.py
index 2c8adc0..73d2e14 100644
--- a/nhentai/command.py
+++ b/nhentai/command.py
@@ -31,13 +31,18 @@ def main():
     else:
         exit(0)
 
-    downloader = Downloader(path=options.output_dir,
-                            thread=options.threads, timeout=options.timeout)
-    for doujinshi in doujinshi_list:
-        doujinshi.downloader = downloader
-        doujinshi.download()
+    if not options.is_show:
+        downloader = Downloader(path=options.output_dir,
+                                thread=options.threads, timeout=options.timeout)
 
-    logger.log(15, u'🍺 All done.')
+        for doujinshi in doujinshi_list:
+            doujinshi.downloader = downloader
+            doujinshi.download()
+
+        logger.log(15, u'🍺 All done.')
+
+    else:
+        [doujinshi.show() for doujinshi in doujinshi_list]
 
 
 def signal_handler(signal, frame):
diff --git a/nhentai/constant.py b/nhentai/constant.py
index 66656a3..0dab75a 100644
--- a/nhentai/constant.py
+++ b/nhentai/constant.py
@@ -1,10 +1,9 @@
 import os
 
-SCHEMA = os.getenv('NHENTAI_SCHEMA', 'https://')
-BASE_URL = os.getenv('NHENTAI', 'nhentai.net')
+BASE_URL = os.getenv('NHENTAI', 'https://nhentai.net')
+
+DETAIL_URL = '%s/g' % BASE_URL
+SEARCH_URL = '%s/search/' % BASE_URL
+IMAGE_URL = 'https://i.%s/galleries' % BASE_URL
 
-URL = '%s%s' % (SCHEMA, BASE_URL)
-DETAIL_URL = '%s/g' % URL
-SEARCH_URL = '%s/search/' % URL
-IMAGE_URL = '%si.%s/galleries' % (SCHEMA, BASE_URL)
 PROXY = {}
diff --git a/nhentai/doujinshi.py b/nhentai/doujinshi.py
index 4bcee71..1e557f2 100644
--- a/nhentai/doujinshi.py
+++ b/nhentai/doujinshi.py
@@ -43,7 +43,7 @@ class Doujinshi(object):
             ["URL", self.url],
             ["Pages", self.pages],
         ]
-        logger.info(u'Print doujinshi information\n{0}'.format(tabulate(table)))
+        logger.info(u'Print doujinshi information of {0}\n{1}'.format(self.id, tabulate(table)))
 
     def download(self):
         logger.info('Start download doujinshi: %s' % self.name)
diff --git a/nhentai/utils.py b/nhentai/utils.py
index dfbc21d..ee3d060 100644
--- a/nhentai/utils.py
+++ b/nhentai/utils.py
@@ -1,10 +1,14 @@
 # coding: utf-8
+
+
 class _Singleton(type):
     """ A metaclass that creates a Singleton base class when called. """
     _instances = {}
+
     def __call__(cls, *args, **kwargs):
         if cls not in cls._instances:
             cls._instances[cls] = super(_Singleton, cls).__call__(*args, **kwargs)
         return cls._instances[cls]
 
+
 class Singleton(_Singleton('SingletonMeta', (object,), {})): pass
\ No newline at end of file