diff --git a/Makefile.am b/Makefile.am
index 2b84467b0c..9b1d31c666 100644
--- a/Makefile.am
+++ b/Makefile.am
@@ -113,6 +113,8 @@ MODULES =					\
   guix/scripts/import/hackage.scm		\
   guix/scripts/environment.scm			\
   guix/scripts/publish.scm			\
+  guix/scripts/edit.scm				\
+  guix/scripts/size.scm				\
   guix.scm					\
   $(GNU_SYSTEM_MODULES)
 
@@ -191,7 +193,8 @@ SCM_TESTS =					\
   tests/syscalls.scm				\
   tests/gremlin.scm				\
   tests/lint.scm				\
-  tests/publish.scm
+  tests/publish.scm				\
+  tests/size.scm
 
 if HAVE_GUILE_JSON
 
@@ -264,7 +267,6 @@ EXTRA_DIST =						\
   build-aux/check-available-binaries.scm		\
   build-aux/check-final-inputs-self-contained.scm	\
   build-aux/download.scm				\
-  build-aux/list-packages.scm				\
   build-aux/make-binary-tarball.scm			\
   srfi/srfi-37.scm.in					\
   srfi/srfi-64.scm					\
diff --git a/build-aux/hydra/demo-os.scm b/build-aux/hydra/demo-os.scm
index d96cdce496..95950cacb1 100644
--- a/build-aux/hydra/demo-os.scm
+++ b/build-aux/hydra/demo-os.scm
@@ -22,22 +22,14 @@
 ;;; machine images that we build.
 ;;;
 
-(use-modules (gnu)
-
-             (gnu packages xorg)
-             (gnu packages avahi)
-             (gnu packages linux)
-             (gnu packages tor)
-
-             (gnu services networking)
-             (gnu services avahi)
-             (gnu services dbus)
-             (gnu services xorg))
+(use-modules (gnu))
+(use-service-modules desktop xorg networking avahi)
+(use-package-modules linux xorg tor avahi)
 
 (operating-system
  (host-name "gnu")
  (timezone "Europe/Paris")
- (locale "en_US.utf8")
+ (locale "en_US.UTF-8")
 
  (bootloader (grub-configuration
               (device "/dev/sda")))
diff --git a/build-aux/list-packages.scm b/build-aux/list-packages.scm
deleted file mode 100755
index c4f445291b..0000000000
--- a/build-aux/list-packages.scm
+++ /dev/null
@@ -1,450 +0,0 @@
-#!/bin/sh
-exec guile -l "$0"                              \
-  -c '(apply (@ (list-packages) list-packages)
-             (cdr (command-line)))'
-!#
-;;; GNU Guix --- Functional package management for GNU
-;;; Copyright © 2013, 2014, 2015 Ludovic Courtès <ludo@gnu.org>
-;;; Copyright © 2013 Alex Sassmannshausen <alex.sassmannshausen@gmail.com>
-;;;
-;;; This file is part of GNU Guix.
-;;;
-;;; GNU Guix is free software; you can redistribute it and/or modify it
-;;; under the terms of the GNU General Public License as published by
-;;; the Free Software Foundation; either version 3 of the License, or (at
-;;; your option) any later version.
-;;;
-;;; GNU Guix is distributed in the hope that it will be useful, but
-;;; WITHOUT ANY WARRANTY; without even the implied warranty of
-;;; MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
-;;; GNU General Public License for more details.
-;;;
-;;; You should have received a copy of the GNU General Public License
-;;; along with GNU Guix.  If not, see <http://www.gnu.org/licenses/>.
-
-(define-module (list-packages)
-  #:use-module (guix utils)
-  #:use-module (guix packages)
-  #:use-module (guix licenses)
-  #:use-module (guix gnu-maintenance)
-  #:use-module ((guix download) #:select (%mirrors))
-  #:use-module ((guix build download) #:select (maybe-expand-mirrors))
-  #:use-module (gnu packages)
-  #:use-module (sxml simple)
-  #:use-module (sxml fold)
-  #:use-module (web uri)
-  #:use-module (ice-9 match)
-  #:use-module (srfi srfi-1)
-  #:export (list-packages))
-
-;;; Commentary:
-;;;
-;;; Emit an HTML representation of the packages available in GNU Guix.
-;;;
-;;; Code:
-
-(define lookup-gnu-package
-  (let ((gnu (official-gnu-packages)))
-    (lambda (name)
-      "Return the package description for GNU package NAME, or #f."
-      (find (lambda (package)
-              (equal? (gnu-package-name package) name))
-            gnu))))
-
-(define (list-join lst item)
-  "Join the items in LST by inserting ITEM between each pair of elements."
-  (let loop ((lst    lst)
-             (result '()))
-    (match lst
-      (()
-       (match (reverse result)
-         (()
-          '())
-         ((_ rest ...)
-          rest)))
-      ((head tail ...)
-       (loop tail
-             (cons* head item result))))))
-
-(define (package->sxml package previous description-ids remaining)
-  "Return 3 values: the HTML-as-SXML for PACKAGE added to all previously
-collected package output in PREVIOUS, a list of DESCRIPTION-IDS and the number
-of packages still to be processed in REMAINING.  Also Introduces a call to the
-JavaScript prep_pkg_descs function as part of the output of PACKAGE, every
-time the length of DESCRIPTION-IDS, increasing, is 15 or when REMAINING,
-decreasing, is 1."
-  (define (location-url loc)
-    (string-append "http://git.savannah.gnu.org/cgit/guix.git/tree/"
-                   (location-file loc) "#n"
-                   (number->string (location-line loc))))
-
-  (define (source-url package)
-    (let ((loc (package-location package)))
-      (and loc (location-url loc))))
-
-  (define (license package)
-    (define ->sxml
-      (match-lambda
-       ((lst ...)
-        `(div ,(map ->sxml lst)))
-       ((? license? license)
-        (let ((uri (license-uri license)))
-          (case (and=> (and uri (string->uri uri)) uri-scheme)
-            ((http https)
-             `(div (a (@ (href ,uri)
-                         (title "Link to the full license"))
-                      ,(license-name license))))
-            (else
-             `(div ,(license-name license) " ("
-                   ,(license-comment license) ")")))))
-       (#f "")))
-
-    (->sxml (package-license package)))
-
-  (define (patches package)
-    (define patch-url
-      (match-lambda
-       ((? string? patch)
-        (string-append
-         "http://git.savannah.gnu.org/cgit/guix.git/tree/gnu/packages/patches/"
-         (basename patch)))
-       ((? origin? patch)
-        (uri->string
-         (first (maybe-expand-mirrors (string->uri
-                                       (match (origin-uri patch)
-                                         ((? string? uri) uri)
-                                         ((head . tail) head)))
-                                      %mirrors))))))
-
-    (define patch-name
-      (match-lambda
-       ((? string? patch)
-        (basename patch))
-       ((? origin? patch)
-        (match (origin-uri patch)
-          ((? string? uri) (basename uri))
-          ((head . tail) (basename head))))))
-
-    (define (snippet-link snippet)
-      (let ((loc (or (package-field-location package 'source)
-                     (package-location package))))
-        `(a (@ (href ,(location-url loc))
-               (title "Link to patch snippet"))
-            "snippet")))
-
-    (and (origin? (package-source package))
-         (let ((patches (origin-patches (package-source package)))
-               (snippet (origin-snippet (package-source package))))
-           (and (or (pair? patches) snippet)
-                `(div "patches: "
-                      ,(let loop ((patches patches)
-                                  (number  1)
-                                  (links   '()))
-                         (match patches
-                           (()
-                            (let* ((additional (and snippet
-                                                    (snippet-link snippet)))
-                                   (links      (if additional
-                                                   (cons additional links)
-                                                   links)))
-                              (list-join (reverse links) ", ")))
-                           ((patch rest ...)
-                            (loop rest
-                                  (+ 1 number)
-                                  (cons `(a (@ (href ,(patch-url patch))
-                                               (title ,(string-append
-                                                        "Link to "
-                                                        (patch-name patch))))
-                                            ,(number->string number))
-                                        links))))))))))
-
-  (define (status package)
-    (define (url system)
-      `(a (@ (href ,(string-append "http://hydra.gnu.org/job/gnu/master/"
-                                   (package-full-name package) "."
-                                   system))
-             (title "View the status of this architecture's build at Hydra"))
-          ,system))
-
-    `(div "status: "
-          ,(list-join (map url
-                           (lset-intersection
-                            string=?
-                            %hydra-supported-systems
-                            (package-transitive-supported-systems package)))
-                      " ")))
-
-  (define (package-logo name)
-    (and=> (lookup-gnu-package name)
-           gnu-package-logo))
-
-  (define (insert-tr description-id js?)
-    (define (insert-js-call description-ids)
-      "Return an sxml call to prep_pkg_descs, with up to 15 elements of
-description-ids as formal parameters."
-      `(script (@ (type "text/javascript"))
-               ,(format #f "prep_pkg_descs(~a)"
-                        (string-append "'"
-                                       (string-join description-ids "', '")
-                                       "'"))))
-
-    (let ((description-ids (cons description-id description-ids)))
-      `(tr (td ,(if (gnu-package? package)
-                    `(img (@ (src "/graphics/gnu-head-mini.png")
-                             (alt "Part of GNU")
-                             (title "Part of GNU")))
-                    ""))
-           (td (a (@ (href ,(source-url package))
-                     (title "Link to the Guix package source code"))
-                  ,(package-name package) " "
-                  ,(package-version package)))
-           (td (span ,(package-synopsis package))
-               (div (@ (id ,description-id))
-                    ,(match (package-logo (package-name package))
-                       ((? string? url)
-                        `(img (@ (src ,url)
-                                 (height "35")
-                                 (class "package-logo")
-                                 (alt ("Logo of " ,(package-name package))))))
-                       (_ #f))
-                    (p ,(package-description package))
-                    ,(license package)
-                    (a (@ (href ,(package-home-page package))
-                          (title "Link to the package's website"))
-                       ,(package-home-page package))
-                    ,(status package)
-                    ,(patches package)
-                    ,(if js?
-                         (insert-js-call description-ids)
-                         ""))))))
-
-  (let ((description-id (symbol->string
-                         (gensym (package-name package)))))
-    (cond ((= remaining 1)              ; Last package in packages
-           (values
-            (reverse                              ; Fold has reversed packages
-             (cons (insert-tr description-id 'js) ; Prefix final sxml
-                   previous))
-            '()                            ; No more work to do
-            0))                            ; End of the line
-          ((= (length description-ids) 15) ; Time for a JS call
-           (values
-            (cons (insert-tr description-id 'js)
-                  previous)    ; Prefix new sxml
-            '()                ; Reset description-ids
-            (1- remaining)))   ; Reduce remaining
-          (else                ; Insert another row, and build description-ids
-           (values
-            (cons (insert-tr description-id #f)
-                  previous)                       ; Prefix new sxml
-            (cons description-id description-ids) ; Update description-ids
-            (1- remaining))))))                   ; Reduce remaining
-
-(define (packages->sxml packages)
-  "Return an HTML page as SXML describing PACKAGES."
-  `(div
-    (h2 "GNU Guix Package List")
-    (div (@ (id "intro"))
-         (div
-          (img (@ (src "graphics/GuixSD-V.png")
-                  (alt "Guix System Distribution")
-                  (height "83"))))
-         (p "This web page lists the packages currently provided by the "
-            (a (@ (href "manual/guix.html#GNU-Distribution"))
-               "Guix System Distribution")
-            ".  "
-            "Our " (a (@ (href "http://hydra.gnu.org/jobset/gnu/master"))
-                      "continuous integration system")
-            " shows their current build status."))
-    (table (@ (id "packages"))
-           (tr (th "GNU?")
-               (th "Package version")
-               (th "Package details"))
-           ,@(fold-values package->sxml packages '() '() (length packages)))
-    (a (@ (href "#intro")
-          (title "Back to top.")
-          (id "top"))
-       "^")))
-
-
-(define (insert-css)
-  "Return the CSS for the list-packages page."
-  (format #t
-"<style>
-/* license: CC0 */
-a {
-    transition: all 0.3s;
-}
-div#intro {
-    margin-bottom: 2em;
-}
-div#intro div, div#intro p {
-    padding:0.5em;
-}
-div#intro div {
-    float:left;
-}
-div#intro img {
-    float:left;
-    padding:0.75em;
-}
-table#packages, table#packages tr, table#packages tbody, table#packages td, table#packages th {
-    border: 0px solid black;
-    clear: both;
-}
-table#packages tr:nth-child(even) {
-    background-color: #FFF;
-}
-table#packages tr:nth-child(odd) {
-    background-color: #EEE;
-}
-table#packages tr:hover, table#packages tr:focus, table#packages tr:active {
-    background-color: #DDD;
-}
-table#packages tr:first-child, table#packages tr:first-child:hover, table#packages tr:first-child:focus, table#packages tr:first-child:active {
-    background-color: #333;
-    color: #fff;
-}
-table#packages td {
-    margin:0px;
-    padding:0.2em 0.5em;
-}
-table#packages td:first-child {
-    width:10%;
-    text-align:center;
-}
-table#packages td:nth-child(2) {
-    width:30%;
-}
-table#packages td:last-child {
-    width:60%;
-}
-img.package-logo {
-    float: left;
-    padding: 0.75em;
-}
-table#packages span {
-    font-weight: 700;
-}
-table#packages span a {
-    float: right;
-    font-weight: 500;
-}
-a#top {
-    position:fixed;
-    right:10px;
-    bottom:10px;
-    font-size:150%;
-    background-color:#EEE;
-    padding:10px 7.5px 0 7.5px;
-    text-decoration:none;
-    color:#000;
-    border-radius:5px;
-}
-a#top:hover, a#top:focus {
-    background-color:#333;
-    color:#fff;
-}
-</style>"))
-
-(define (insert-js)
-  "Return the JavaScript for the list-packages page."
-  (format #t
-"<script type=\"text/javascript\">
-// license: CC0
-function show_hide(idThing)
-{
-  if(document.getElementById && document.createTextNode) {
-    var thing = document.getElementById(idThing);
-    /* Used to change the link text, depending on whether description is
-       collapsed or expanded */
-    var thingLink = thing.previousSibling.lastChild.firstChild;
-    if (thing) {
-      if (thing.style.display == \"none\") {
-        thing.style.display = \"\";
-        thingLink.data = 'Collapse';
-      } else {
-        thing.style.display = \"none\";
-        thingLink.data = 'Expand';
-      }
-    }
-  }
-}
-/* Add controllers used for collapse/expansion of package descriptions */
-function prep(idThing)
-{
-  var tdThing = document.getElementById(idThing).parentNode;
-  if (tdThing) {
-    var aThing = tdThing.firstChild.appendChild(document.createElement('a'));
-    aThing.setAttribute('href', 'javascript:void(0)');
-    aThing.setAttribute('title', 'show/hide package description');
-    aThing.appendChild(document.createTextNode('Expand'));
-    aThing.onclick=function(){show_hide(idThing);};
-    /* aThing.onkeypress=function(){show_hide(idThing);}; */
-  }
-}
-/* Take n element IDs, prepare them for javascript enhanced
-   display and hide the IDs by default. */
-function prep_pkg_descs()
-{
-  if(document.getElementById && document.createTextNode) {
-    for(var i=0; i<arguments.length; i++) {
-      prep(arguments[i])
-      show_hide(arguments[i]);
-    }
-  }
-}
-</script>"))
-
-
-(define (list-packages . args)
-  "Return an HTML page listing all the packages found in the GNU distribution,
-with gnu.org server-side include and all that."
-  ;; Don't attempt to translate descriptions.
-  (setlocale LC_ALL "C")
-
-  ;; Output the page as UTF-8 since that's what the gnu.org server-side
-  ;; headers claim.
-  (set-port-encoding! (current-output-port) "UTF-8")
-
-  (let ((packages (sort (fold-packages cons '())
-                        (lambda (p1 p2)
-                          (string<? (package-name p1) (package-name p2))))))
-   (format #t "<!--#include virtual=\"/server/html5-header.html\" -->
-<!-- Parent-Version: 1.70 $ -->
-<title>GNU Guix - GNU Distribution - GNU Project</title>
-")
-   (insert-css)
-   (insert-js)
-   (format #t "<!--#include virtual=\"/server/banner.html\" -->")
-
-   (sxml->xml (packages->sxml packages))
-   (format #t "</div>
-<!--#include virtual=\"/server/footer.html\" -->
-<div id=\"footer\">
-
-<p>Please send general FSF &amp; GNU inquiries to
-<a href=\"mailto:gnu@gnu.org\">&lt;gnu@gnu.org&gt;</a>.
-There are also <a href=\"/contact/\">other ways to contact</a>
-the FSF.  Broken links and other corrections or suggestions can be sent
-to <a href=\"mailto:bug-guix@gnu.org\">&lt;bug-guix@gnu.org&gt;</a>.</p>
-
-<p>Copyright &copy; 2013 Free Software Foundation, Inc.</p>
-
-<p>This page is licensed under a <a rel=\"license\"
-href=\"http://creativecommons.org/licenses/by-nd/3.0/us/\">Creative
-Commons Attribution-NoDerivs 3.0 United States License</a>.</p>
-
-<p>Updated:
-<!-- timestamp start -->
-$Date$
-<!-- timestamp end -->
-</p>
-</div>
-</div>
-</body>
-</html>
-"))
-  )
-
-;;; list-packages.scm ends here
diff --git a/doc.am b/doc.am
index de232a87a4..ee896c189b 100644
--- a/doc.am
+++ b/doc.am
@@ -90,6 +90,7 @@ SUBCOMMANDS :=					\
   archive					\
   build						\
   download					\
+  edit						\
   environment					\
   gc						\
   hash						\
@@ -99,6 +100,7 @@ SUBCOMMANDS :=					\
   publish					\
   pull						\
   refresh					\
+  size						\
   system
 
 $(eval $(foreach subcommand,$(SUBCOMMANDS),			\
@@ -106,5 +108,11 @@ $(eval $(foreach subcommand,$(SUBCOMMANDS),			\
 
 dist_man1_MANS =				\
   doc/guix.1					\
-  doc/guix-daemon.1				\
   $(SUBCOMMANDS:%=doc/guix-%.1)
+
+if BUILD_DAEMON
+
+dist_man1_MANS +=				\
+  doc/guix-daemon.1
+
+endif
diff --git a/doc/contributing.texi b/doc/contributing.texi
index 536f223da4..7b16ea3539 100644
--- a/doc/contributing.texi
+++ b/doc/contributing.texi
@@ -203,14 +203,32 @@ standards, GNU Coding Standards}); you can check the commit history for
 examples.
 
 Before submitting a patch that adds or modifies a package definition,
-please run @code{guix lint @var{package}}, where @var{package} is the
+please run through this check list:
+
+@enumerate
+@item
+Run @code{guix lint @var{package}}, where @var{package} is the
 name of the new or modified package, and fix any errors it reports
-(@pxref{Invoking guix lint}).  In addition, please make sure the package
-builds on your platform, using @code{guix build @var{package}}.  You may
-also want to check that dependent package (if applicable) are not
-affected by the change; @code{guix refresh --list-dependent
+(@pxref{Invoking guix lint}).
+
+@item
+Make sure the package builds on your platform, using @code{guix build
+@var{package}}.
+
+@item
+Take a look at the profile reported by @command{guix size}
+(@pxref{Invoking guix size}).  This will allow you to notice references
+to other packages unwillingly retained.  It may also help determine
+whether to split the package (@pxref{Packages with Multiple Outputs}),
+and which optional dependencies should be used.
+
+@item
+For important changes, check that dependent package (if applicable) are
+not affected by the change; @code{guix refresh --list-dependent
 @var{package}} will help you do that (@pxref{Invoking guix refresh}).
 
+@end enumerate
+
 When posting a patch to the mailing list, use @samp{[PATCH] @dots{}} as a
 subject.  You may use your email client or the @command{git send-mail}
 command.
diff --git a/doc/guix.texi b/doc/guix.texi
index f707b5c58f..a669464feb 100644
--- a/doc/guix.texi
+++ b/doc/guix.texi
@@ -124,11 +124,13 @@ Defining Packages
 Utilities
 
 * Invoking guix build::         Building packages from the command line.
+* Invoking guix edit::          Editing package definitions.
 * Invoking guix download::      Downloading a file and printing its hash.
 * Invoking guix hash::          Computing the cryptographic hash of a file.
 * Invoking guix import::        Importing package definitions.
 * Invoking guix refresh::       Updating package definitions.
 * Invoking guix lint::          Finding errors in package definitions.
+* Invoking guix size::          Profiling disk usage.
 * Invoking guix environment::   Setting up development environments.
 * Invoking guix publish::       Sharing substitutes.
 
@@ -1494,7 +1496,8 @@ graphical user interfaces (GUIs).  The former depend solely on the C
 library, whereas the latter depend on Tcl/Tk and the underlying X
 libraries.  In this case, we leave the command-line tools in the default
 output, whereas the GUIs are in a separate output.  This allows users
-who do not need the GUIs to save space.
+who do not need the GUIs to save space.  The @command{guix size} command
+can help find out about such situations (@pxref{Invoking guix size}).
 
 There are several such multiple-output packages in the GNU distribution.
 Other conventional output names include @code{lib} for libraries and
@@ -1574,11 +1577,15 @@ as arguments.
 
 @item --requisites
 @itemx -R
+@cindex closure
 List the requisites of the store files passed as arguments.  Requisites
 include the store files themselves, their references, and the references
 of these, recursively.  In other words, the returned list is the
 @dfn{transitive closure} of the store files.
 
+@xref{Invoking guix size}, for a tool to profile the size of an
+element's closure.
+
 @end table
 
 Lastly, the following options allow you to check the integrity of the
@@ -1931,7 +1938,10 @@ unavailable to the build process, possibly leading to a build failure.
 
 Once a package definition is in place, the
 package may actually be built using the @code{guix build} command-line
-tool (@pxref{Invoking guix build}).  @xref{Packaging Guidelines}, for
+tool (@pxref{Invoking guix build}).  You can easily jump back to the
+package definition using the @command{guix edit} command
+(@pxref{Invoking guix edit}).
+@xref{Packaging Guidelines}, for
 more information on how to test package definitions, and
 @ref{Invoking guix lint}, for information on how to check a definition
 for style conformance.
@@ -3261,11 +3271,13 @@ programming interface of Guix in a convenient way.
 
 @menu
 * Invoking guix build::         Building packages from the command line.
+* Invoking guix edit::          Editing package definitions.
 * Invoking guix download::      Downloading a file and printing its hash.
 * Invoking guix hash::          Computing the cryptographic hash of a file.
 * Invoking guix import::        Importing package definitions.
 * Invoking guix refresh::       Updating package definitions.
 * Invoking guix lint::          Finding errors in package definitions.
+* Invoking guix size::          Profiling disk usage.
 * Invoking guix environment::   Setting up development environments.
 * Invoking guix publish::       Sharing substitutes.
 @end menu
@@ -3548,6 +3560,28 @@ the parsed command-line options.
 @end defvr
 
 
+@node Invoking guix edit
+@section Invoking @command{guix edit}
+
+@cindex package definition, editing
+So many packages, so many source files!  The @command{guix edit} command
+facilitates the life of packagers by pointing their editor at the source
+file containing the definition of the specified packages.  For instance:
+
+@example
+guix edit gcc-4.8 vim
+@end example
+
+@noindent
+launches the program specified in the @code{EDITOR} environment variable
+to edit the recipe of GCC@tie{}4.8.4 and that of Vim.
+
+If you are using Emacs, note that the Emacs user interface provides
+similar functionality in the ``package info'' buffers created by
+@kbd{M-x guix-search-by-name} and similar commands (@pxref{Emacs
+Commands}).
+
+
 @node Invoking guix download
 @section Invoking @command{guix download}
 
@@ -3947,6 +3981,73 @@ and exit.
 
 @end table
 
+@node Invoking guix size
+@section Invoking @command{guix size}
+
+The @command{guix size} command helps package developers profile the
+disk usage of packages.  It is easy to overlook the impact of an
+additional dependency added to a package, or the impact of using a
+single output for a package that could easily be split (@pxref{Packages
+with Multiple Outputs}).  These are the typical issues that
+@command{guix size} can highlight.
+
+The command can be passed a package specification such as @code{gcc-4.8}
+or @code{guile:debug}, or a file name in the store.  Consider this
+example:
+
+@example
+$ guix size coreutils
+store item                               total    self
+/gnu/store/@dots{}-coreutils-8.23          70.0    13.9  19.8%
+/gnu/store/@dots{}-gmp-6.0.0a              55.3     2.5   3.6%
+/gnu/store/@dots{}-acl-2.2.52              53.7     0.5   0.7%
+/gnu/store/@dots{}-attr-2.4.46             53.2     0.3   0.5%
+/gnu/store/@dots{}-gcc-4.8.4-lib           52.9    15.7  22.4%
+/gnu/store/@dots{}-glibc-2.21              37.2    37.2  53.1%
+@end example
+
+@cindex closure
+The store items listed here constitute the @dfn{transitive closure} of
+Coreutils---i.e., Coreutils and all its dependencies, recursively---as
+would be returned by:
+
+@example
+$ guix gc -R /gnu/store/@dots{}-coreutils-8.23
+@end example
+
+Here the output shows 3 columns next to store items.  The first column,
+labeled ``total'', shows the size in mebibytes (MiB) of the closure of
+the store item---that is, its own size plus the size of all its
+dependencies.  The next column, labeled ``self'', shows the size of the
+item itself.  The last column shows the ratio of the item's size to the
+space occupied by all the items listed here.
+
+In this example, we see that the closure of Coreutils weighs in at
+70@tie{}MiB, half of which is taken by libc.  (That libc represents a
+large fraction of the closure is not a problem @i{per se} because it is
+always available on the system anyway.)
+
+When the package passed to @command{guix size} is available in the
+store, @command{guix size} queries the daemon to determine its
+dependencies, and measures its size in the store, similar to @command{du
+-ms --apparent-size} (@pxref{du invocation,,, coreutils, GNU
+Coreutils}).
+
+When the given package is @emph{not} in the store, @command{guix size}
+reports information based on information about the available substitutes
+(@pxref{Substitutes}).  This allows it to profile disk usage of store
+items that are not even on disk, only available remotely.
+
+A single option is available:
+
+@table @option
+
+@item --system=@var{system}
+@itemx -s @var{system}
+Consider packages for @var{system}---e.g., @code{x86_64-linux}.
+
+@end table
+
 @node Invoking guix environment
 @section Invoking @command{guix environment}
 
@@ -4606,8 +4707,8 @@ Linux @dfn{pluggable authentication module} (PAM) services.
 List of string-valued G-expressions denoting setuid programs.
 @xref{Setuid Programs}.
 
-@item @code{sudoers} (default: @var{%sudoers-specification})
-@cindex sudoers
+@item @code{sudoers-file} (default: @var{%sudoers-specification})
+@cindex sudoers file
 The contents of the @file{/etc/sudoers} file as a file-like object
 (@pxref{G-Expressions, @code{local-file} and @code{plain-file}}).
 
diff --git a/gnu/build/install.scm b/gnu/build/install.scm
index 32fbe8efbc..9085e22e09 100644
--- a/gnu/build/install.scm
+++ b/gnu/build/install.scm
@@ -161,20 +161,27 @@ as created and modified at the Epoch."
                   (utime file 0 0 0 0))))
             (find-files directory "")))
 
-(define (register-closure store closure)
+(define* (register-closure store closure
+                           #:key (deduplicate? #t))
   "Register CLOSURE in STORE, where STORE is the directory name of the target
 store and CLOSURE is the name of a file containing a reference graph as used
-by 'guix-register'.  As a side effect, this resets timestamps on store files."
-  (let ((status (system* "guix-register" "--prefix" store
-                         closure)))
+by 'guix-register'.  As a side effect, this resets timestamps on store files
+and, if DEDUPLICATE? is true, deduplicates files common to CLOSURE and the
+rest of STORE."
+  (let ((status (apply system* "guix-register" "--prefix" store
+                       (append (if deduplicate? '() '("--no-deduplication"))
+                               (list closure)))))
     (unless (zero? status)
       (error "failed to register store items" closure))))
 
 (define* (populate-single-profile-directory directory
-                                            #:key profile closure)
+                                            #:key profile closure
+                                            deduplicate?)
   "Populate DIRECTORY with a store containing PROFILE, whose closure is given
 in the file called CLOSURE (as generated by #:references-graphs.)  DIRECTORY
 is initialized to contain a single profile under /root pointing to PROFILE.
+DEDUPLICATE? determines whether to deduplicate files in the store.
+
 This is used to create the self-contained Guix tarball."
   (define (scope file)
     (string-append directory "/" file))
@@ -190,7 +197,8 @@ This is used to create the self-contained Guix tarball."
 
   ;; Populate the store.
   (populate-store (list closure) directory)
-  (register-closure (canonicalize-path directory) closure)
+  (register-closure (canonicalize-path directory) closure
+                    #:deduplicate? deduplicate?)
 
   ;; XXX: 'guix-register' registers profiles as GC roots but the symlink
   ;; target uses $TMPDIR.  Fix that.
diff --git a/gnu/packages.scm b/gnu/packages.scm
index 9eb4877be8..6e46a890bb 100644
--- a/gnu/packages.scm
+++ b/gnu/packages.scm
@@ -51,7 +51,8 @@
 
             check-package-freshness
 
-            specification->package))
+            specification->package
+            specification->package+output))
 
 ;;; Commentary:
 ;;;
@@ -418,3 +419,36 @@ present, return the preferred newest version."
            (leave (_ "~A: package not found for version ~a~%")
                   name version)
            (leave (_ "~A: unknown package~%") name))))))
+
+(define* (specification->package+output spec #:optional (output "out"))
+  "Return the package and output specified by SPEC, or #f and #f; SPEC may
+optionally contain a version number and an output name, as in these examples:
+
+  guile
+  guile-2.0.9
+  guile:debug
+  guile-2.0.9:debug
+
+If SPEC does not specify a version number, return the preferred newest
+version; if SPEC does not specify an output, return OUTPUT."
+  (define (ensure-output p sub-drv)
+    (if (member sub-drv (package-outputs p))
+        sub-drv
+        (leave (_ "package `~a' lacks output `~a'~%")
+               (package-full-name p)
+               sub-drv)))
+
+  (let-values (((name version sub-drv)
+                (package-specification->name+version+output spec output)))
+    (match (find-best-packages-by-name name version)
+      ((p)
+       (values p (ensure-output p sub-drv)))
+      ((p p* ...)
+       (warning (_ "ambiguous package specification `~a'~%")
+                spec)
+       (warning (_ "choosing ~a from ~a~%")
+                (package-full-name p)
+                (location->string (package-location p)))
+       (values p (ensure-output p sub-drv)))
+      (()
+       (leave (_ "~a: package not found~%") spec)))))
diff --git a/gnu/packages/bioinformatics.scm b/gnu/packages/bioinformatics.scm
index 0d8a6d518c..12c9175ed3 100644
--- a/gnu/packages/bioinformatics.scm
+++ b/gnu/packages/bioinformatics.scm
@@ -1,5 +1,6 @@
 ;;; GNU Guix --- Functional package management for GNU
 ;;; Copyright © 2014, 2015 Ricardo Wurmus <rekado@elephly.net>
+;;; Copyright © 2015 Ben Woodcroft <donttrustben@gmail.com>
 ;;;
 ;;; This file is part of GNU Guix.
 ;;;
@@ -28,6 +29,7 @@
   #:use-module (guix build-system python)
   #:use-module (guix build-system trivial)
   #:use-module (gnu packages)
+  #:use-module (gnu packages algebra)
   #:use-module (gnu packages base)
   #:use-module (gnu packages boost)
   #:use-module (gnu packages compression)
@@ -87,7 +89,7 @@ BAM files.")
 (define-public bedops
   (package
     (name "bedops")
-    (version "2.4.5")
+    (version "2.4.14")
     (source (origin
               (method url-fetch)
               (uri (string-append "https://github.com/bedops/bedops/archive/v"
@@ -95,7 +97,7 @@ BAM files.")
               (file-name (string-append name "-" version ".tar.gz"))
               (sha256
                (base32
-                "0wmg6j0icimlrnsidaxrzf3hfgjvlkkcwvpdg7n4gg7hdv2m9ni5"))))
+                "1kqbac547wyqma81cyky9n7mkgikjpsfd3nnmcm6hpqwanqgh10v"))))
     (build-system gnu-build-system)
     (arguments
      '(#:tests? #f
@@ -615,6 +617,56 @@ file formats including SAM/BAM, Wiggle/BigWig, BED, GFF/GTF, VCF.")
 other types of unwanted sequence from high-throughput sequencing reads.")
     (license license:expat)))
 
+(define-public diamond
+  (package
+    (name "diamond")
+    (version "0.7.9")
+    (source (origin
+              (method url-fetch)
+              (uri (string-append
+                    "https://github.com/bbuchfink/diamond/archive/v"
+                    version ".tar.gz"))
+              (file-name (string-append name "-" version ".tar.gz"))
+              (sha256
+               (base32
+                "0hfkcfv9f76h5brbyw9fyvmc0l9cmbsxrcdqk0fa9xv82zj47p15"))
+              (snippet '(begin
+                          (delete-file "bin/diamond")
+                          #t))))
+    (build-system gnu-build-system)
+    (arguments
+     '(#:tests? #f  ;no "check" target
+       #:phases
+       (modify-phases %standard-phases
+         (add-after 'unpack 'enter-source-dir
+                    (lambda _
+                      (chdir "src")
+                      #t))
+         (delete 'configure)
+         (replace 'install
+                  (lambda* (#:key outputs #:allow-other-keys)
+                    (let ((bin (string-append (assoc-ref outputs "out")
+                                              "/bin")))
+                      (mkdir-p bin)
+                      (copy-file "../bin/diamond"
+                                 (string-append bin "/diamond"))
+                      #t))))))
+    (native-inputs
+     `(("bc" ,bc)))
+    (inputs
+     `(("boost" ,boost)
+       ("zlib" ,zlib)))
+    (home-page "https://github.com/bbuchfink/diamond")
+    (synopsis "Accelerated BLAST compatible local sequence aligner")
+    (description
+     "DIAMOND is a BLAST-compatible local aligner for mapping protein and
+translated DNA query sequences against a protein reference database (BLASTP
+and BLASTX alignment mode).  The speedup over BLAST is up to 20,000 on short
+reads at a typical sensitivity of 90-99% relative to BLAST depending on the
+data and settings.")
+    (license (license:non-copyleft "file://src/COPYING"
+                                   "See src/COPYING in the distribution."))))
+
 (define-public edirect
   (package
     (name "edirect")
@@ -1063,7 +1115,7 @@ sequencing tag position and orientation.")
     (source (origin
               (method url-fetch)
               (uri (string-append
-                    "http://pypi.python.org/packages/source/m/misopy/misopy-"
+                    "https://pypi.python.org/packages/source/m/misopy/misopy-"
                     version ".tar.gz"))
               (sha256
                (base32
diff --git a/gnu/packages/ebook.scm b/gnu/packages/ebook.scm
index 2be5ea351a..670fc64de8 100644
--- a/gnu/packages/ebook.scm
+++ b/gnu/packages/ebook.scm
@@ -60,7 +60,7 @@
 (define-public calibre
   (package
     (name "calibre")
-    (version "2.29.0")
+    (version "2.30.0")
     (source
       (origin
         (method url-fetch)
@@ -69,7 +69,7 @@
                             version ".tar.xz"))
         (sha256
           (base32
-           "1n3cfnjnghhhsgzcbcvbr0gh191lhl6az09q1s68jhlcc2lski6l"))
+           "1k2rpn06nfzqjy5k6fh8pwfj8vbhpn7rgkpkkpz5n2fqg3z8ph1j"))
         ;; Remove non-free or doubtful code, see
         ;; https://lists.gnu.org/archive/html/guix-devel/2015-02/msg00478.html
         (modules '((guix build utils)))
diff --git a/gnu/packages/freedesktop.scm b/gnu/packages/freedesktop.scm
index c5b55f30a2..eeb97cdc85 100644
--- a/gnu/packages/freedesktop.scm
+++ b/gnu/packages/freedesktop.scm
@@ -38,7 +38,9 @@
   #:use-module (gnu packages docbook)
   #:use-module (gnu packages glib)                ;intltool
   #:use-module (gnu packages xdisorg)
-  #:use-module (gnu packages xorg))
+  #:use-module (gnu packages xorg)
+  #:use-module (gnu packages doxygen)
+  #:use-module (gnu packages libffi))
 
 (define-public xdg-utils
   (package
@@ -197,3 +199,36 @@ Python")
 
 (define-public python2-pyxdg
   (package-with-python2 python-pyxdg))
+
+(define-public wayland
+  (package
+    (name "wayland")
+    (version "1.8.1")
+    (source (origin
+              (method url-fetch)
+              (uri (string-append "http://wayland.freedesktop.org/releases/"
+                                  name "-" version ".tar.xz"))
+              (sha256
+               (base32
+                "1j3gfzn8i0xhk3j34mwb2srrscjxfyi279jhyq80mz943j6r6z7i"))))
+    (build-system gnu-build-system)
+    (native-inputs
+     `(("doxygen" ,doxygen)
+       ("pkg-config" ,pkg-config)
+       ("xmlto" ,xmlto)
+       ("xsltproc" ,libxslt)))
+    (inputs
+     `(("docbook-xml" ,docbook-xml)
+       ("docbook-xsl" ,docbook-xsl)
+       ("expat" ,expat)
+       ("libffi" ,libffi)
+       ("libxml2" ,libxml2))) ; for XML_CATALOG_FILES
+    (home-page "http://wayland.freedesktop.org/")
+    (synopsis "Display server protocol")
+    (description
+     "Wayland is a protocol for a compositor to talk to its clients as well as
+a C library implementation of that protocol.  The compositor can be a standalone
+display server running on Linux kernel modesetting and evdev input devices, an X
+application, or a wayland client itself.  The clients can be traditional
+applications, X servers (rootless or fullscreen) or other display servers.")
+    (license license:x11)))
diff --git a/gnu/packages/image.scm b/gnu/packages/image.scm
index a7483ba94a..ad4acb787e 100644
--- a/gnu/packages/image.scm
+++ b/gnu/packages/image.scm
@@ -582,3 +582,26 @@ with lossy compression and typically provides 3x smaller file sizes compared
 to PNG when lossy compression is acceptable for the red/green/blue color
 channels.")
     (license license:bsd-3)))
+
+(define-public libmng
+  (package
+    (name "libmng")
+    (version "2.0.3")
+    (source (origin
+              (method url-fetch)
+              (uri (string-append "mirror://sourceforge/libmng/"
+                                  name "-" version ".tar.xz"))
+              (sha256
+               (base32
+                "1lvxnpds0vcf0lil6ia2036ghqlbl740c4d2sz0q5g6l93fjyija"))))
+    (build-system gnu-build-system)
+    (propagated-inputs
+     ;; These are all in the 'Libs.private' field of libmng.pc.
+     `(("lcms" ,lcms)
+       ("libjpeg" ,libjpeg)
+       ("zlib" ,zlib)))
+    (home-page "http://www.libmng.com/")
+    (synopsis "Library for handling MNG files")
+    (description
+     "Libmng is the MNG (Multiple-image Network Graphics) reference library.")
+    (license license:bsd-3)))
diff --git a/gnu/packages/ocaml.scm b/gnu/packages/ocaml.scm
index 5baf24cac0..84841d017c 100644
--- a/gnu/packages/ocaml.scm
+++ b/gnu/packages/ocaml.scm
@@ -24,12 +24,12 @@
   #:use-module (guix utils)
   #:use-module (guix build-system gnu)
   #:use-module (gnu packages)
+  #:use-module (gnu packages gcc)
   #:use-module (gnu packages base)
   #:use-module (gnu packages emacs)
   #:use-module (gnu packages texinfo)
   #:use-module (gnu packages pkg-config)
   #:use-module (gnu packages compression)
-  #:use-module (gnu packages commencement)
   #:use-module (gnu packages xorg)
   #:use-module (gnu packages texlive)
   #:use-module (gnu packages perl)
@@ -57,8 +57,9 @@
        ("pkg-config" ,pkg-config)))
     (inputs
      `(("libx11" ,libx11)
-       ("gcc:lib" ,gcc-final "lib") ; for libiberty, needed for objdump support
-       ("zlib" ,zlib)))             ; also needed for objdump support
+       ;; For libiberty, needed for objdump support.
+       ("gcc:lib" ,(canonical-package gcc-4.8) "lib")
+       ("zlib" ,zlib)))                       ;also needed for objdump support
     (arguments
      `(#:modules ((guix build gnu-build-system)
                   (guix build utils)
diff --git a/gnu/packages/package-management.scm b/gnu/packages/package-management.scm
index 7f6ec56151..3da9df92cc 100644
--- a/gnu/packages/package-management.scm
+++ b/gnu/packages/package-management.scm
@@ -166,7 +166,7 @@ the Nix package manager.")
   ;;
   ;; Note: use a short commit id; when using the long one, the limit on socket
   ;; file names is exceeded while running the tests.
-  (let ((commit "a43b55f"))
+  (let ((commit "684bf7c"))
     (package (inherit guix-0.8.2)
       (version (string-append "0.8.2." commit))
       (source (origin
@@ -176,7 +176,7 @@ the Nix package manager.")
                       (commit commit)))
                 (sha256
                  (base32
-                  "1r0l8gfh5nxc1j0sqj8ywkg280k9qbj7zsk33z84rvl7l0nwnk88"))
+                  "0fq9ajj17kbb0f1p79al2vcqah9sl0imayhggcp31c3vq0ahya9g"))
                 (file-name (string-append "guix-" version "-checkout"))))
       (arguments
        (substitute-keyword-arguments (package-arguments guix-0.8.2)
diff --git a/gnu/packages/qt.scm b/gnu/packages/qt.scm
index 3bc3145e8d..1cf72e1586 100644
--- a/gnu/packages/qt.scm
+++ b/gnu/packages/qt.scm
@@ -29,6 +29,8 @@
   #:use-module (gnu packages)
   #:use-module (gnu packages bison)
   #:use-module (gnu packages compression)
+  #:use-module (gnu packages cups)
+  #:use-module (gnu packages databases)
   #:use-module (gnu packages fontutils)
   #:use-module (gnu packages flex)
   #:use-module (gnu packages gl)
@@ -93,7 +95,7 @@ X11 (yet).")
 (define-public qt
   (package
     (name "qt")
-    (version "5.4.1")
+    (version "5.4.2")
     (source (origin
              (method url-fetch)
              (uri (string-append "http://download.qt-project.org/official_releases/qt/"
@@ -103,7 +105,7 @@ X11 (yet).")
                                  version ".tar.xz"))
              (sha256
               (base32
-               "0q6qzakq8xihw91xv310qi3vyylq7x2bzdkjgy8sqxii2lgbjzhv"))
+               "09gay5cimfdb0apy60v7z4r4zkl2vjysdppzihpla8dp2c30fvcc"))
              (patches (list (search-patch "qt5-conflicting-typedefs.patch")
                             (search-patch "qt5-runpath.patch")))
              (snippet
@@ -119,12 +121,14 @@ webrtc/tools/e2e_quality/audio/perf")))))
     (inputs
      `(("alsa-lib" ,alsa-lib)
        ("dbus" ,dbus)
+       ("cups" ,cups)
        ("expat" ,expat)
        ("fontconfig" ,fontconfig)
        ("freetype" ,freetype)
        ("glib" ,glib)
        ("icu4c" ,icu4c)
        ("libjpeg" ,libjpeg)
+       ("libmng" ,libmng)
        ("libpci" ,pciutils)
        ("libpng" ,libpng)
        ("libx11" ,libx11)
@@ -143,10 +147,12 @@ webrtc/tools/e2e_quality/audio/perf")))))
        ("mysql" ,mysql)
        ("nss" ,nss)
        ("openssl" ,openssl)
+       ("postgresql" ,postgresql)
        ("pulseaudio" ,pulseaudio)
        ("pcre" ,pcre)
        ("sqlite" ,sqlite)
        ("udev" ,eudev)
+       ("unixodbc" ,unixodbc)
        ("xcb-util" ,xcb-util)
        ("xcb-util-image" ,xcb-util-image)
        ("xcb-util-keysyms" ,xcb-util-keysyms)
@@ -221,7 +227,7 @@ developers using C++ or QML, a CSS & JavaScript like language.")
 
 (define-public qt-4
   (package (inherit qt)
-    (version "4.8.6")
+    (version "4.8.7")
     (source (origin
              (method url-fetch)
              (uri (string-append "http://download.qt-project.org/official_releases/qt/"
@@ -231,7 +237,7 @@ developers using C++ or QML, a CSS & JavaScript like language.")
                                  version ".tar.gz"))
              (sha256
               (base32
-               "0b036iqgmbbv37dgwwfihw3mihjbnw3kb5kaisdy0qi8nn8xs54b"))
+               "183fca7n7439nlhxyg1z7aky0izgbyll3iwakw4gwivy16aj5272"))
              (patches (map search-patch
                            '("qt4-ldflags.patch" "qt4-tests.patch")))))
     (inputs `(,@(alist-delete "libjpeg" (package-inputs qt))
diff --git a/gnu/packages/samba.scm b/gnu/packages/samba.scm
index 8e53debcb3..d7223bc0ba 100644
--- a/gnu/packages/samba.scm
+++ b/gnu/packages/samba.scm
@@ -168,14 +168,14 @@ Desktops into Active Directory environments using the winbind daemon.")
 (define-public talloc
   (package
     (name "talloc")
-    (version "2.1.0")
+    (version "2.1.2")
     (source (origin
               (method url-fetch)
-              (uri (string-append "http://www.samba.org/ftp/talloc/talloc-"
+              (uri (string-append "https://www.samba.org/ftp/talloc/talloc-"
                                   version ".tar.gz"))
               (sha256
                (base32
-                "13zh628hzlp2v9vj70knnfac2xbxqrdhgap30csq4zv4h8w3j087"))))
+                "13c365f7y8idjf2v1jxdjpkc3lxdmsxxfxjx1ymianm7zjiph393"))))
     (build-system gnu-build-system)
     (arguments
      '(#:phases (alist-replace
diff --git a/gnu/system.scm b/gnu/system.scm
index 92ed454b2c..565d6c10c7 100644
--- a/gnu/system.scm
+++ b/gnu/system.scm
@@ -1,6 +1,7 @@
 ;;; GNU Guix --- Functional package management for GNU
 ;;; Copyright © 2013, 2014, 2015 Ludovic Courtès <ludo@gnu.org>
 ;;; Copyright © 2015 Mark H Weaver <mhw@netris.org>
+;;; Copyright © 2015 Alex Kost <alezost@gmail.com>
 ;;;
 ;;; This file is part of GNU Guix.
 ;;;
@@ -148,8 +149,8 @@
   (setuid-programs operating-system-setuid-programs
                    (default %setuid-programs))    ; list of string-valued gexps
 
-  (sudoers operating-system-sudoers               ; file-like
-           (default %sudoers-specification)))
+  (sudoers-file operating-system-sudoers-file     ; file-like
+                (default %sudoers-specification)))
 
 
 ;;;
@@ -440,7 +441,7 @@ on SHELLS.  /etc/shells is used by xterm, polkit, and other programs."
                         (pam-services '())
                         (profile "/run/current-system/profile")
                         hosts-file nss (shells '())
-                        (sudoers (plain-file "sudoers" "")))
+                        (sudoers-file (plain-file "sudoers" "")))
   "Return a derivation that builds the static part of the /etc directory."
   (mlet* %store-monad
       ((pam.d      (pam-services->directory pam-services))
@@ -540,7 +541,7 @@ fi\n"))
                   ("hosts" ,#~#$hosts-file)
                   ("localtime" ,#~(string-append #$tzdata "/share/zoneinfo/"
                                                  #$timezone))
-                  ("sudoers" ,sudoers)))))
+                  ("sudoers" ,sudoers-file)))))
 
 (define (operating-system-profile os)
   "Return a derivation that builds the system profile of OS."
@@ -624,9 +625,9 @@ use 'plain-file' instead~%")
                   #:timezone (operating-system-timezone os)
                   #:hosts-file /etc/hosts
                   #:shells shells
-                  #:sudoers (maybe-string->file
-                             "sudoers"
-                             (operating-system-sudoers os))
+                  #:sudoers-file (maybe-string->file
+                                  "sudoers"
+                                  (operating-system-sudoers-file os))
                   #:profile profile-drv)))
 
 (define %setuid-programs
diff --git a/gnu/system/install.scm b/gnu/system/install.scm
index e8a36b3def..6f4116ef9b 100644
--- a/gnu/system/install.scm
+++ b/gnu/system/install.scm
@@ -63,15 +63,19 @@ under /root/.guix-profile where GUIX is installed."
           (setenv "PATH"
                   (string-append #$guix "/sbin:" #$tar "/bin:" #$xz "/bin"))
 
+          ;; Note: there is not much to gain here with deduplication and there
+          ;; is the overhead of the '.links' directory, so turn it off.
           (populate-single-profile-directory %root
                                              #:profile #$profile
-                                             #:closure "profile")
+                                             #:closure "profile"
+                                             #:deduplicate? #f)
 
           ;; Create the tarball.  Use GNU format so there's no file name
           ;; length limitation.
           (with-directory-excursion %root
             (zero? (system* "tar" "--xz" "--format=gnu"
                             "--owner=root:0" "--group=root:0"
+                            "--check-links"
                             "-cvf" #$output
                             ;; Avoid adding / and /var to the tarball,
                             ;; so that the ownership and permissions of those
diff --git a/guix/gnu-maintenance.scm b/guix/gnu-maintenance.scm
index 8d47cee487..ac83df40a3 100644
--- a/guix/gnu-maintenance.scm
+++ b/guix/gnu-maintenance.scm
@@ -192,15 +192,22 @@ network to check in GNU's database."
                   ;; Definitely non-GNU.
                   'non-gnu)))))
 
-       (let ((url  (and=> (package-source package) origin-uri))
-             (name (package-name package)))
-         (case (and (string? url) (mirror-type url))
-           ((gnu) #t)
-           ((non-gnu) #f)
-           (else
-            ;; Last resort: resort to the network.
-            (and (member name (map gnu-package-name (official-gnu-packages)))
-                 #t))))))))
+       (define (gnu-home-page? package)
+         (and=> (package-home-page package)
+                (lambda (url)
+                  (and=> (uri-host (string->uri url))
+                         (lambda (host)
+                           (member host '("www.gnu.org" "gnu.org")))))))
+
+       (or (gnu-home-page? package)
+           (let ((url  (and=> (package-source package) origin-uri))
+                 (name (package-name package)))
+             (case (and (string? url) (mirror-type url))
+               ((gnu) #t)
+               ((non-gnu) #f)
+               (else
+                (and (member name (map gnu-package-name (official-gnu-packages)))
+                     #t)))))))))
 
 
 ;;;
diff --git a/guix/scripts/archive.scm b/guix/scripts/archive.scm
index ea6801a6eb..ab2fc46c31 100644
--- a/guix/scripts/archive.scm
+++ b/guix/scripts/archive.scm
@@ -27,6 +27,8 @@
   #:use-module (guix ui)
   #:use-module (guix pki)
   #:use-module (guix pk-crypto)
+  #:use-module (guix scripts build)
+  #:use-module (gnu packages)
   #:use-module (ice-9 match)
   #:use-module (ice-9 format)
   #:use-module (ice-9 rdelim)
@@ -34,8 +36,6 @@
   #:use-module (srfi srfi-11)
   #:use-module (srfi srfi-26)
   #:use-module (srfi srfi-37)
-  #:use-module (guix scripts build)
-  #:use-module (guix scripts package)
   #:use-module (rnrs io ports)
   #:export (guix-archive))
 
diff --git a/guix/scripts/edit.scm b/guix/scripts/edit.scm
new file mode 100644
index 0000000000..fc453ac38d
--- /dev/null
+++ b/guix/scripts/edit.scm
@@ -0,0 +1,79 @@
+;;; GNU Guix --- Functional package management for GNU
+;;; Copyright © 2015 Ludovic Courtès <ludo@gnu.org>
+;;;
+;;; This file is part of GNU Guix.
+;;;
+;;; GNU Guix is free software; you can redistribute it and/or modify it
+;;; under the terms of the GNU General Public License as published by
+;;; the Free Software Foundation; either version 3 of the License, or (at
+;;; your option) any later version.
+;;;
+;;; GNU Guix is distributed in the hope that it will be useful, but
+;;; WITHOUT ANY WARRANTY; without even the implied warranty of
+;;; MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+;;; GNU General Public License for more details.
+;;;
+;;; You should have received a copy of the GNU General Public License
+;;; along with GNU Guix.  If not, see <http://www.gnu.org/licenses/>.
+
+(define-module (guix scripts edit)
+  #:use-module (guix ui)
+  #:use-module (guix utils)
+  #:use-module (guix packages)
+  #:use-module (gnu packages)
+  #:use-module (srfi srfi-1)
+  #:use-module (srfi srfi-37)
+  #:export (%editor
+            guix-edit))
+
+(define %options
+  (list (option '(#\h "help") #f #f
+                (lambda args
+                  (show-help)
+                  (exit 0)))
+        (option '(#\V "version") #f #f
+                (lambda args
+                  (show-version-and-exit "guix edit")))))
+
+(define (show-help)
+  (display (_ "Usage: guix edit PACKAGE...
+Start $EDITOR to edit the definitions of PACKAGE...\n"))
+  (newline)
+  (display (_ "
+  -h, --help             display this help and exit"))
+  (display (_ "
+  -V, --version          display version information and exit"))
+  (newline)
+  (show-bug-report-information))
+
+(define %editor
+  (make-parameter (or (getenv "EDITOR") "emacsclient")))
+
+(define (search-path* path file)
+  "Like 'search-path' but exit if FILE is not found."
+  (let ((absolute-file-name (search-path path file)))
+    (unless absolute-file-name
+      ;; Shouldn't happen unless somebody fiddled with the 'location' field.
+      (leave (_ "file '~a' not found in search path ~s~%")
+             file path))
+    absolute-file-name))
+
+
+(define (guix-edit . args)
+  (with-error-handling
+    (let* ((specs    (parse-command-line args %options '(())
+                                         #:argument-handler cons))
+           (packages (map specification->package specs)))
+      (for-each (lambda (package)
+                  (unless (package-location package)
+                    (leave (_ "source location of package '~a' is unknown~%")
+                           (package-full-name package))))
+                packages)
+      (apply execlp (%editor) (%editor)
+             (append-map (lambda (package)
+                           (let ((loc (package-location package)))
+                             (list (string-append "+"
+                                                  (number->string
+                                                   (location-line loc)))
+                                   (search-path* %load-path (location-file loc)))))
+                         packages)))))
diff --git a/guix/scripts/offload.scm b/guix/scripts/offload.scm
index e65125741f..e6be8b4465 100644
--- a/guix/scripts/offload.scm
+++ b/guix/scripts/offload.scm
@@ -606,9 +606,7 @@ defines a total order on machines.)"
           ((machine1 slot1)
            (match b
              ((machine2 slot2)
-              (if (pred machine1 machine2)
-                  (list machine1 slot1)
-                  (list machine2 slot2))))))))
+              (pred machine1 machine2)))))))
 
     (let loop ((machines+slots
                 (sort machines+slots
diff --git a/guix/scripts/package.scm b/guix/scripts/package.scm
index d9f38fb8bc..56a6e2db64 100644
--- a/guix/scripts/package.scm
+++ b/guix/scripts/package.scm
@@ -47,8 +47,7 @@
   #:use-module (gnu packages base)
   #:use-module (gnu packages guile)
   #:use-module ((gnu packages bootstrap) #:select (%bootstrap-guile))
-  #:export (specification->package+output
-            switch-to-generation
+  #:export (switch-to-generation
             switch-to-previous-generation
             roll-back
             delete-generation
@@ -324,39 +323,6 @@ similar."
           (primitive-_exit 0)
           (apply throw args)))))
 
-(define* (specification->package+output spec #:optional (output "out"))
-  "Return the package and output specified by SPEC, or #f and #f; SPEC may
-optionally contain a version number and an output name, as in these examples:
-
-  guile
-  guile-2.0.9
-  guile:debug
-  guile-2.0.9:debug
-
-If SPEC does not specify a version number, return the preferred newest
-version; if SPEC does not specify an output, return OUTPUT."
-  (define (ensure-output p sub-drv)
-    (if (member sub-drv (package-outputs p))
-        sub-drv
-        (leave (_ "package `~a' lacks output `~a'~%")
-               (package-full-name p)
-               sub-drv)))
-
-  (let-values (((name version sub-drv)
-                (package-specification->name+version+output spec output)))
-    (match (find-best-packages-by-name name version)
-      ((p)
-       (values p (ensure-output p sub-drv)))
-      ((p p* ...)
-       (warning (_ "ambiguous package specification `~a'~%")
-                spec)
-       (warning (_ "choosing ~a from ~a~%")
-                (package-full-name p)
-                (location->string (package-location p)))
-       (values p (ensure-output p sub-drv)))
-      (()
-       (leave (_ "~a: package not found~%") spec)))))
-
 (define (upgradeable? name current-version current-path)
   "Return #t if there's a version of package NAME newer than CURRENT-VERSION,
 or if the newest available version is equal to CURRENT-VERSION but would have
diff --git a/guix/scripts/size.scm b/guix/scripts/size.scm
new file mode 100644
index 0000000000..41dd6043a7
--- /dev/null
+++ b/guix/scripts/size.scm
@@ -0,0 +1,247 @@
+;;; GNU Guix --- Functional package management for GNU
+;;; Copyright © 2015 Ludovic Courtès <ludo@gnu.org>
+;;;
+;;; This file is part of GNU Guix.
+;;;
+;;; GNU Guix is free software; you can redistribute it and/or modify it
+;;; under the terms of the GNU General Public License as published by
+;;; the Free Software Foundation; either version 3 of the License, or (at
+;;; your option) any later version.
+;;;
+;;; GNU Guix is distributed in the hope that it will be useful, but
+;;; WITHOUT ANY WARRANTY; without even the implied warranty of
+;;; MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+;;; GNU General Public License for more details.
+;;;
+;;; You should have received a copy of the GNU General Public License
+;;; along with GNU Guix.  If not, see <http://www.gnu.org/licenses/>.
+
+(define-module (guix scripts size)
+  #:use-module (guix ui)
+  #:use-module (guix store)
+  #:use-module (guix monads)
+  #:use-module (guix utils)
+  #:use-module (guix packages)
+  #:use-module (guix derivations)
+  #:use-module (gnu packages)
+  #:use-module (srfi srfi-1)
+  #:use-module (srfi srfi-9)
+  #:use-module (srfi srfi-11)
+  #:use-module (srfi srfi-34)
+  #:use-module (srfi srfi-37)
+  #:use-module (ice-9 ftw)
+  #:use-module (ice-9 match)
+  #:use-module (ice-9 format)
+  #:export (profile?
+            profile-file
+            profile-self-size
+            profile-closure-size
+            store-profile
+
+            guix-size))
+
+;; Size profile of a store item.
+(define-record-type <profile>
+  (profile file self-size closure-size)
+  profile?
+  (file          profile-file)                 ;store item
+  (self-size     profile-self-size)            ;size in bytes
+  (closure-size  profile-closure-size))        ;size of dependencies in bytes
+
+(define (file-size file)
+  "Return the size of bytes of FILE, entering it if FILE is a directory."
+  (file-system-fold (const #t)
+                    (lambda (file stat result)    ;leaf
+                      (+ (stat:size stat) result))
+                    (lambda (directory stat result) ;down
+                      (+ (stat:size stat) result))
+                    (lambda (directory stat result) ;up
+                      result)
+                    (lambda (file stat result)    ;skip
+                      result)
+                    (lambda (file stat errno result)
+                      (format (current-error-port)
+                              "file-size: ~a: ~a~%" file
+                              (strerror errno))
+                      result)
+                    0
+                    file
+                    lstat))
+
+(define substitutable-path-info*
+  (store-lift substitutable-path-info))
+
+(define (store-item-exists? item)
+  "Return #t if ITEM is in the store, and protect it from GC.  Otherwise
+return #f."
+  (lambda (store)
+    (add-temp-root store item)
+    (values (valid-path? store item) store)))
+
+(define (file-size* item)
+  "Like 'file-size', but resort to information from substitutes if ITEM is not
+in the store."
+  (mlet %store-monad ((exists? (store-item-exists? item)))
+    (if exists?
+        (return (file-size item))
+        (mlet %store-monad ((info (substitutable-path-info* (list item))))
+          (match info
+            ((info)
+             ;; The nar size is an approximation, but a good one.
+             (return (substitutable-nar-size info)))
+            (()
+             (leave (_ "no available substitute information for '~a'~%")
+                    item)))))))
+
+(define* (display-profile profile #:optional (port (current-output-port)))
+  "Display PROFILE, a list of PROFILE objects, to PORT."
+  (define MiB (expt 2 20))
+
+  (format port "~64a ~8a ~a\n"
+          (_ "store item") (_ "total") (_ "self"))
+  (let ((whole (reduce + 0 (map profile-self-size profile))))
+    (for-each (match-lambda
+                (($ <profile> name self total)
+                 (format port "~64a  ~6,1f  ~6,1f ~5,1f%\n"
+                         name (/ total MiB) (/ self MiB)
+                         (* 100. (/ self whole 1.)))))
+              (sort profile
+                    (match-lambda*
+                      ((($ <profile> _ _ total1) ($ <profile> _ _ total2))
+                       (> total1 total2)))))))
+
+(define display-profile*
+  (lift display-profile %store-monad))
+
+(define (substitutable-requisites store item)
+  "Return the list of requisites of ITEM based on information available in
+substitutes."
+  (let loop ((items  (list item))
+             (result '()))
+    (match items
+      (()
+       (delete-duplicates result))
+      (items
+       (let ((info (substitutable-path-info store
+                                            (delete-duplicates items))))
+         (loop (remove (lambda (item)             ;XXX: complexity
+                         (member item result))
+                       (append-map substitutable-references info))
+               (append (append-map substitutable-references info)
+                       result)))))))
+
+(define (requisites* item)
+  "Return as a monadic value the requisites of ITEMS, based either on the
+information available in the local store or using information about
+substitutes."
+  (lambda (store)
+    (guard (c ((nix-protocol-error? c)
+               (values (substitutable-requisites store item)
+                       store)))
+      (values (requisites store item) store))))
+
+(define (store-profile item)
+  "Return as a monadic value a list of <profile> objects representing the
+profile of ITEM and its requisites."
+  (mlet* %store-monad ((refs  (>>= (requisites* item)
+                                   (lambda (refs)
+                                     (return (delete-duplicates
+                                              (cons item refs))))))
+                       (sizes (mapm %store-monad
+                                    (lambda (item)
+                                      (>>= (file-size* item)
+                                           (lambda (size)
+                                             (return (cons item size)))))
+                                    refs)))
+    (define (dependency-size item)
+      (mlet %store-monad ((deps (requisites* item)))
+        (foldm %store-monad
+               (lambda (item total)
+                 (return (+ (assoc-ref sizes item) total)))
+               0
+               (delete-duplicates (cons item deps)))))
+
+    (mapm %store-monad
+          (match-lambda
+            ((item . size)
+             (mlet %store-monad ((dependencies (dependency-size item)))
+               (return (profile item size dependencies)))))
+          sizes)))
+
+(define* (ensure-store-item spec-or-item
+                            #:key dry-run?)
+  "Return a store file name.  If SPEC-OR-ITEM is a store file name, return it
+as is.  Otherwise, assume SPEC-OR-ITEM is a package output specification such
+as \"guile:debug\" or \"gcc-4.8\" and return its store file name."
+  (with-monad %store-monad
+    (if (store-path? spec-or-item)
+        (return spec-or-item)
+        (let-values (((package output)
+                      (specification->package+output spec-or-item)))
+          (mlet %store-monad ((drv (package->derivation package)))
+            ;; Note: we don't try building DRV like 'guix archive' does
+            ;; because we don't have to since we can instead rely on
+            ;; substitute meta-data.
+            (return (derivation->output-path drv output)))))))
+
+
+;;;
+;;; Options.
+;;;
+
+(define (show-help)
+  (display (_ "Usage: guix size [OPTION]... PACKAGE
+Report the size of PACKAGE and its dependencies.\n"))
+  (display (_ "
+  -s, --system=SYSTEM    consider packages for SYSTEM--e.g., \"i686-linux\""))
+  (newline)
+  (display (_ "
+  -h, --help             display this help and exit"))
+  (display (_ "
+  -V, --version          display version information and exit"))
+  (newline)
+  (show-bug-report-information))
+
+(define %options
+  ;; Specifications of the command-line options.
+  (list (option '(#\s "system") #t #f
+                (lambda (opt name arg result)
+                  (alist-cons 'system arg
+                              (alist-delete 'system result eq?))))
+        (option '(#\h "help") #f #f
+                (lambda args
+                  (show-help)
+                  (exit 0)))
+        (option '(#\V "version") #f #f
+                (lambda args
+                  (show-version-and-exit "guix size")))))
+
+(define %default-options
+  `((system . ,(%current-system))))
+
+
+;;;
+;;; Entry point.
+;;;
+
+(define (guix-size . args)
+  (with-error-handling
+    (let* ((opts     (parse-command-line args %options (list %default-options)))
+           (files    (filter-map (match-lambda
+                                   (('argument . file) file)
+                                   (_ #f))
+                                 opts))
+           (system   (assoc-ref opts 'system))
+           (dry-run? (assoc-ref opts 'dry-run?)))
+      (match files
+        (()
+         (leave (_ "missing store item argument\n")))
+        ((file)
+         (with-store store
+           (run-with-store store
+             (mlet* %store-monad ((item    (ensure-store-item file))
+                                  (profile (store-profile item)))
+               (display-profile* profile))
+             #:system system)))
+        ((files ...)
+         (leave (_ "too many arguments\n")))))))
diff --git a/po/guix/POTFILES.in b/po/guix/POTFILES.in
index 4f27f54d6c..247fe2cf6a 100644
--- a/po/guix/POTFILES.in
+++ b/po/guix/POTFILES.in
@@ -16,6 +16,8 @@ guix/scripts/authenticate.scm
 guix/scripts/system.scm
 guix/scripts/lint.scm
 guix/scripts/publish.scm
+guix/scripts/edit.scm
+guix/scripts/size.scm
 guix/gnu-maintenance.scm
 guix/ui.scm
 guix/http-client.scm
diff --git a/tests/size.scm b/tests/size.scm
new file mode 100644
index 0000000000..95b99a88ef
--- /dev/null
+++ b/tests/size.scm
@@ -0,0 +1,87 @@
+;;; GNU Guix --- Functional package management for GNU
+;;; Copyright © 2015 Ludovic Courtès <ludo@gnu.org>
+;;;
+;;; This file is part of GNU Guix.
+;;;
+;;; GNU Guix is free software; you can redistribute it and/or modify it
+;;; under the terms of the GNU General Public License as published by
+;;; the Free Software Foundation; either version 3 of the License, or (at
+;;; your option) any later version.
+;;;
+;;; GNU Guix is distributed in the hope that it will be useful, but
+;;; WITHOUT ANY WARRANTY; without even the implied warranty of
+;;; MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+;;; GNU General Public License for more details.
+;;;
+;;; You should have received a copy of the GNU General Public License
+;;; along with GNU Guix.  If not, see <http://www.gnu.org/licenses/>.
+
+(define-module (test-size)
+  #:use-module (guix store)
+  #:use-module (guix monads)
+  #:use-module (guix packages)
+  #:use-module (guix derivations)
+  #:use-module (guix gexp)
+  #:use-module (guix tests)
+  #:use-module (guix scripts size)
+  #:use-module (gnu packages bootstrap)
+  #:use-module (ice-9 match)
+  #:use-module (srfi srfi-1)
+  #:use-module (srfi srfi-64))
+
+(define %store
+  (open-connection-for-tests))
+
+(define-syntax-rule (test-assertm name exp)
+  (test-assert name
+    (run-with-store %store exp
+                    #:guile-for-build (%guile-for-build))))
+
+
+(test-begin "size")
+
+(test-assertm "store-profile"
+  (mlet* %store-monad ((file1 (gexp->derivation "file1"
+                                                #~(symlink #$%bootstrap-guile
+                                                           #$output)))
+                       (file2 (text-file* "file2"
+                                          "the file => " file1)))
+    (define (matching-profile item)
+      (lambda (profile)
+        (string=? item (profile-file profile))))
+
+    (mbegin %store-monad
+      (built-derivations (list file2))
+      (mlet %store-monad ((profiles (store-profile
+                                     (derivation->output-path file2)))
+                          (guile    (package->derivation %bootstrap-guile)))
+        (define (lookup-profile drv)
+          (find (matching-profile (derivation->output-path drv))
+                profiles))
+
+        (letrec-syntax ((match* (syntax-rules (=>)
+                                  ((_ ((drv => profile) rest ...) body)
+                                   (match (lookup-profile drv)
+                                     ((? profile? profile)
+                                      (match* (rest ...) body))))
+                                  ((_ () body)
+                                   body))))
+          ;; Make sure we get all three profiles with sensible values.
+          (return (and (= (length profiles) 3)
+                       (match* ((file1 => profile1)
+                                (file2 => profile2)
+                                (guile => profile3))
+                         (and (> (profile-closure-size profile2) 0)
+                              (= (profile-closure-size profile2)
+                                 (+ (profile-self-size profile1)
+                                    (profile-self-size profile2)
+                                    (profile-self-size profile3))))))))))))
+
+(test-end "size")
+
+
+(exit (= (test-runner-fail-count (test-runner-current)) 0))
+
+;;; Local Variables:
+;;; eval: (put 'match* 'scheme-indent-function 1)
+;;; End: