diff --git a/src/ecofind.c b/src/ecofind.c
index c622f23..735feef 100644
--- a/src/ecofind.c
+++ b/src/ecofind.c
@@ -61,6 +61,8 @@ static void PrintHelp()
         PP		"-h	: [H]elp - print <this> help\n\n");
         PP      "<taxon> name pattern bearing regular expressions\n\n");
         PP      "------------------------------------------\n");
+        PP		" https://www.grenoble.prabi.fr/trac/ecoPCR/wiki");
+        PP      "------------------------------------------\n\n");
 }
 
 /* ----------------------------------------------- */
@@ -102,6 +104,13 @@ int main(int argc, char **argv)
 	
 	if ((argc - optind) < 1)
         errflag++;
+	
+	if (prefix == NULL)
+	{
+		prefix = getenv("ECOPCRDB");
+		if (prefix == NULL)
+			errflag++;
+	}
 		
 	if (errflag)
 		ExitUsage(errflag);