fix the version issue.

modules/motus/downloaddb/main.nf

@@ -30,9 +30,12 @@ process MOTUS_DOWNLOADDB {
     ## clean up
     rm ${software}
 
+    ## mOTUs version number is not available from command line.
+    ## mOTUs save the version number in index database folder.
+    ## mOTUs will check the database version is same version as exec version.
     cat <<-END_VERSIONS > versions.yml
     "${task.process}":
-        mOTUs: \$(echo \$(motus -h 2>&1) | sed 's/^.*Version: //; s/Reference.*\$//')
+        mOTUs: \$(grep motus db_mOTU/db_mOTU_versions | sed 's/motus\\t//g')
     END_VERSIONS
     """
 }