Resolve the issue on Alpine

This resolve the issue #208 :
This remove the "/" in the regex and order the server by only mean ping if the mean deviation is not present.

openpyn/openpyn.py

@@ -530,7 +530,7 @@ def ping_servers(better_servers_list: List, pings: str, stats: bool) -> List:
                     stdout=subprocess.PIPE)
             # pipe the output of ping to grep.
             ping_output = subprocess.check_output(
-                ["grep", "-B", "1", "min/avg/max/"], stdin=ping_proc.stdout)
+                ["grep", "-B", "1", "min/avg/max"], stdin=ping_proc.stdout)
 
             ping_string = str(ping_output)
             # logger.debug(ping_string)
@@ -557,8 +557,12 @@ def ping_servers(better_servers_list: List, pings: str, stats: bool) -> List:
         ping_result.append(ping_list)
         # logger.debug(ping_result)
         pinged_servers_list.append(ping_result)
-    # sort by Ping Avg and Median Deviation
-    pinged_servers_list = sorted(pinged_servers_list, key=lambda item: (item[1][1], item[1][3]))
+    if len(pinged_servers_list[0][1]) >= 4:
+        # sort by Ping Avg and Median Deviation
+        pinged_servers_list = sorted(pinged_servers_list, key=lambda item: (item[1][1], item[1][3]))
+    else:
+        # sort by Ping Avg
+        pinged_servers_list = sorted(pinged_servers_list, key=lambda item: item[1][1])
     return pinged_servers_list