diff --git a/README.md b/README.md
new file mode 100644
--- /dev/null
+++ b/README.md
@@ -0,0 +1,20 @@
+odebuild command
+----------------
+
+This package includes on-the-fly build command 'odebuild'.
+
+```
+Usage: odebuild clean
+       odebuild prepare [options] [-- [cabal-debian-options]]
+       odebuild source [options] [-- [cabal-debian-options [-- [debuild-options]]]
+       odebuild build [options] [-- [cabal-debian-options [-- [debuild-options]]]
+       odebuild install [options] [-- [cabal-debian-options [-- [debuild-options]]]
+       odebuild reinstall [options] [-- [cabal-debian-options [-- [debuild-options]]]
+         reinstall (Remove and install) support only for Haskell library packages
+
+      --revision=DEBIAN_REVISION      debian package revision to pass to cabal-debian
+                                      revision string may use on auto-generating debian directory
+      --install-deps                  install build depends before running build
+      --mode={All|Bin|Src|Dep|Indep}  add build-mode to build-mode list to specify
+  -R  --reuse-source                  not clean generated source directory, and build operation will reuse it
+```
diff --git a/debian-build.cabal b/debian-build.cabal
--- a/debian-build.cabal
+++ b/debian-build.cabal
@@ -1,5 +1,5 @@
 name:                debian-build
-version:             0.10.2.0
+version:             0.10.2.1
 synopsis:            Debian package build sequence tools
 description:         This package provides build sequence functions
                      for debian package, and includes on-the-fly
@@ -9,11 +9,13 @@
 license-file:        LICENSE
 author:              Kei Hibino
 maintainer:          ex8k.hibino@gmail.com
-copyright:           Copyright (c) 2014-2019 Kei Hibino
+copyright:           Copyright (c) 2014-2021 Kei Hibino
 category:            Debian
 build-type:          Simple
 cabal-version:       >=1.10
-tested-with:           GHC == 8.8.1
+tested-with:           GHC == 9.0.1
+                     , GHC == 8.10.1, GHC == 8.10.2, GHC == 8.10.3, GHC == 8.10.4
+                     , GHC == 8.8.1, GHC == 8.8.2, GHC == 8.8.3, GHC == 8.8.4
                      , GHC == 8.6.1, GHC == 8.6.2, GHC == 8.6.3, GHC == 8.6.4, GHC == 8.6.5
                      , GHC == 8.4.1, GHC == 8.4.2, GHC == 8.4.3, GHC == 8.4.4
                      , GHC == 8.2.1, GHC == 8.2.2
@@ -22,6 +24,7 @@
                      , GHC == 7.8.1, GHC == 7.8.2, GHC == 7.8.3, GHC == 7.8.4
                      , GHC == 7.6.1, GHC == 7.6.2, GHC == 7.6.3
                      , GHC == 7.4.1, GHC == 7.4.2
+extra-source-files:  README.md
 
 library
   exposed-modules:
diff --git a/mains/odebuild.hs b/mains/odebuild.hs
--- a/mains/odebuild.hs
+++ b/mains/odebuild.hs
@@ -47,8 +47,10 @@
 descs :: [OptDescr (ODebuildOptions -> Either String ODebuildOptions)]
 descs =
   [ Option [] ["revision"]
-    (ReqArg (\s opts -> return $ opts { revision = Just s }) "DEBIAN_REVISION")
-    "debian package revision to pass to cabal-debian"
+    (ReqArg (\s opts -> return $ opts { revision = Just s }) "DEBIAN_REVISION") $
+    unlines
+    ["debian package revision to pass to cabal-debian",
+     "revision string may use on auto-generating debian directory"]
   , Option [] ["install-deps"]
     (NoArg $ \opts   -> return $ opts { installDeps = True })
     "install build depends before running build"
@@ -60,7 +62,7 @@
     "add build-mode to build-mode list to specify"
   , Option ['R'] ["reuse-source"]
     (NoArg $ \opts   -> return $ opts { reuseSource = True })
-    "not clean generated source directory, and build will reuse it"
+    "not clean generated source directory, and build operation will reuse it"
   ]
 
 modesEx :: String
@@ -79,14 +81,13 @@
   let opts  = "[options]"
       debOpts = "[-- [cabal-debian-options [-- [debuild-options]]]"
       msg = unlines $ map unwords
-            [ [prog, "clean"]
-            , [prog, "prepare", opts, "[-- [cabal-debian-options]]"]
-            , [prog, "source", opts, debOpts]
-            , [prog, "build", opts, debOpts]
-            , [prog, "install", opts, debOpts]
-            , [prog, "reinstall", opts, debOpts]
-            , ["  reinstall (Remove and install) support only for Haskell"]
-            , ["  Revision string may use on auto-generating debian directory."]
+            [ ["Usage:", prog, "clean"]
+            , ["      ", prog, "prepare", opts, "[-- [cabal-debian-options]]"]
+            , ["      ", prog, "source", opts, debOpts]
+            , ["      ", prog, "build", opts, debOpts]
+            , ["      ", prog, "install", opts, debOpts]
+            , ["      ", prog, "reinstall", opts, debOpts]
+            , ["      ", "  reinstall (Remove and install) support only for Haskell library packages"]
             ]
   putStr $ usageInfo msg descs