diff --git a/README.md b/README.md
index 0752888..28b1b3e 100644
--- a/README.md
+++ b/README.md
@@ -28,11 +28,12 @@ package is called `ghc` there, not `ghc-mod`) and install the
 
 ### Nix & NixOS
 
-The installation is a little more involved in this environment as Nix needs some
-ugly hacks to get packages using the GHC API to work, please refer to this
-stackoverflow answer:
-
-http://stackoverflow.com/a/24228830
+`ghc-mod` works fine for users of Nix who follow a recent version of the
+package database such as the `nixos-15.09` or `nixos-unstable` channel. Just
+include the package `ghc-mod` into your `ghcWithPackages` environment like any
+other library. The [Nixpkgs Haskell User's
+Guide](http://hydra.nixos.org/job/nixpkgs/trunk/manual/latest/download-by-type/doc/manual#users-guide-to-the-haskell-infrastructure)
+covers this subject in gret detail.
 
 ## Using the development version
 
diff --git a/elisp/ghc-command.el b/elisp/ghc-command.el
index 7970a12..df9a69f 100644
--- a/elisp/ghc-command.el
+++ b/elisp/ghc-command.el
@@ -53,7 +53,7 @@
       (let ((inhibit-field-text-motion t))
         (sort-subr nil 'forward-line 'end-of-line
 		   (lambda ()
-		     (re-search-forward "^import\\( *qualified\\)? *" nil t)
+		     (re-search-forward "^import +\\(qualified\\)? *" nil t)
 		     nil)
 		   'end-of-line))
       (ghc-merge-lines))))
@@ -64,7 +64,7 @@
     (while (not (eolp))
       ;; qualified modlues are not merged at this moment.
       ;; fixme if it is improper.
-      (if (looking-at "^import *\\([A-Z][^ \n]+\\) *(\\(.*\\))$")
+      (if (looking-at "^import +\\([A-Z][^ \n]+\\) *(\\(.*\\))$")
 	  (let ((mod (match-string-no-properties 1))
 		(syms (match-string-no-properties 2))
 		(beg (point)))
@@ -73,7 +73,7 @@
 	(forward-line)))))
 
 (defun ghc-merge-line (beg mod syms)
-  (let ((regex (concat "^import *" (regexp-quote mod) " *(\\(.*\\))$"))
+  (let ((regex (concat "^import +" (regexp-quote mod) " *(\\(.*\\))$"))
 	duplicated)
     (while (looking-at regex)
       (setq duplicated t)
diff --git a/elisp/ghc-comp.el b/elisp/ghc-comp.el
index 2209ca2..20be9a1 100644
--- a/elisp/ghc-comp.el
+++ b/elisp/ghc-comp.el
@@ -265,7 +265,7 @@ unloaded modules are loaded")
   (let (ret)
     (save-excursion
       (goto-char (point-min))
-      (while (re-search-forward "^import\\( *qualified\\)? +\\([^\n ]+\\)" nil t)
+      (while (re-search-forward "^import +\\(qualified\\)? *\\([^\n ]+\\)" nil t)
 	(ghc-add ret (match-string-no-properties 2))
 	(forward-line)))
     ret))
diff --git a/elisp/ghc-ins-mod.el b/elisp/ghc-ins-mod.el
index 14db867..d567ec2 100644
--- a/elisp/ghc-ins-mod.el
+++ b/elisp/ghc-ins-mod.el
@@ -56,7 +56,7 @@
 
 (defun ghc-goto-module-position ()
   (goto-char (point-max))
-  (if (re-search-backward "^import" nil t)
+  (if (re-search-backward "^import +" nil t)
       (ghc-goto-empty-line)
     (if (not (re-search-backward "^module" nil t))
 	(goto-char (point-min))
diff --git a/elisp/ghc.el b/elisp/ghc.el
index bdad76c..0c4f967 100644
--- a/elisp/ghc.el
+++ b/elisp/ghc.el
@@ -138,7 +138,8 @@
 	(el-ver ghc-version)
 	(ghc-ver (ghc-run-ghc-mod '("--version") "ghc"))
 	(ghc-mod-ver (ghc-run-ghc-mod '("version")))
-	(path (getenv "PATH")))
+	(path (getenv "PATH"))
+	(debug (ghc-run-ghc-mod '("debug")))) ;; before switching buffers.
     (switch-to-buffer (get-buffer-create "**GHC Debug**"))
     (erase-buffer)
     (insert "Path: check if you are using intended programs.\n")
@@ -150,7 +151,10 @@
     (insert (format "\t %s\n" ghc-mod-ver))
     (insert (format "\t%s\n" ghc-ver))
     (insert "\nEnvironment variables:\n")
-    (insert (format "\tPATH=%s\n" path))))
+    (insert (format "\tPATH=%s\n" path))
+    (insert "\nThe result of \"ghc-mod debug\":\n")
+    (insert debug)
+    (goto-char (point-min))))
 
 (defun ghc-insert-template-or-signature (&optional flag)
   (interactive "P")