diff --git a/scripts/Makefile.am b/scripts/Makefile.am
index 35bb926af6..94df32b249 100644
--- a/scripts/Makefile.am
+++ b/scripts/Makefile.am
@@ -1,5 +1,6 @@
 bin_SCRIPTS = nix-collect-garbage \
- nix-pull nix-push nix-prefetch-url
+ nix-pull nix-push nix-prefetch-url \
+ nix-install-package
 
 noinst_SCRIPTS = nix-profile.sh
 
@@ -12,8 +13,8 @@ install-exec-local:
 
 include ../substitute.mk
 
-EXTRA_DIST = nix-switch.in nix-collect-garbage.in \
+EXTRA_DIST = nix-collect-garbage.in \
  nix-pull.in nix-push.in nix-profile.sh.in \
- nix-prefetch-url.in \
+ nix-prefetch-url.in nix-install-package.in \
  prebuilts.conf
 
diff --git a/scripts/nix-install-package.in b/scripts/nix-install-package.in
new file mode 100644
index 0000000000..4988606c3a
--- /dev/null
+++ b/scripts/nix-install-package.in
@@ -0,0 +1,37 @@
+#! /usr/bin/perl -w
+
+use strict;
+use POSIX qw(tmpnam);
+
+my $pkgfile = $ARGV[0];
+die unless defined $pkgfile;
+
+my $tmpdir;
+do { $tmpdir = tmpnam(); }
+until mkdir $tmpdir, 0777;
+
+# !!! remove tmpdir on exit
+
+print "unpacking $pkgfile in $tmpdir...\n";
+system "bunzip2 < $pkgfile | (cd $tmpdir && tar xf -)";
+die if $?;
+
+print "this package contains the following derivations:\n";
+system "nix-env -qsf $tmpdir/default.nix";
+die if $?;
+
+print "do you wish to install them (y/n)? ";
+my $reply = <STDIN>;
+chomp $reply;
+exit if (!($reply eq "y"));
+
+print "pulling caches...\n";
+system "nix-pull `cat $tmpdir/caches`";
+die if $?;
+
+print "installing package...\n";
+system "nix-env -i $tmpdir/default.nix '*'";
+die if $?;
+
+print "installing succeeded! (enter to continue)\n";
+<STDIN>;
diff --git a/scripts/nix-pull.in b/scripts/nix-pull.in
index ad21b6f8ab..1453a46ac9 100644
--- a/scripts/nix-pull.in
+++ b/scripts/nix-pull.in
@@ -19,86 +19,98 @@ my @sucs;
 
 my $fullexpr = "[";
 
-open CONFFILE, "<$conffile";
 
-while (<CONFFILE>) {
+sub processURL {
+    my $url = shift;
+    $url =~ s/\/$//;
+    print "obtaining list of Nix archives at $url...\n";
 
-    chomp;
-    if (/^\s*(\S+)\s*(\#.*)?$/) {
-        my $url = $1;
-        $url =~ s/\/$//;
-
-        print "obtaining list of Nix archives at $url...\n";
-
-        system "wget --cache=off '$url'/MANIFEST -O '$manifest' 2> /dev/null"; # !!! escape
-        if ($?) { die "`wget' failed"; }
+    system "wget --cache=off '$url'/MANIFEST -O '$manifest' 2> /dev/null"; # !!! escape
+    if ($?) { die "`wget' failed"; }
         
-        open MANIFEST, "<$manifest";
+    open MANIFEST, "<$manifest";
 
-        my $inside = 0;
+    my $inside = 0;
 
-        my $storepath;
-        my $narname;
-        my $hash;
-        my @preds;
+    my $storepath;
+    my $narname;
+    my $hash;
+    my @preds;
 
-        while (<MANIFEST>) {
-            chomp;
-            s/\#.*$//g;
-            next if (/^$/);
+    while (<MANIFEST>) {
+        chomp;
+        s/\#.*$//g;
+        next if (/^$/);
 
-            if (!$inside) {
-                if (/^\{$/) { 
-                    $inside = 1;
-                    undef $storepath;
-                    undef $narname;
-                    undef $hash;
-                    @preds = ();
+        if (!$inside) {
+            if (/^\{$/) { 
+                $inside = 1;
+                undef $storepath;
+                undef $narname;
+                undef $hash;
+                @preds = ();
                 }
-                else { die "bad line: $_"; }
-            } else {
-                if (/^\}$/) {
-                    $inside = 0;
-                    my $fullurl = "$url/$narname";
-                    print "$storepath\n";
+            else { die "bad line: $_"; }
+        } else {
+            if (/^\}$/) {
+                $inside = 0;
+                my $fullurl = "$url/$narname";
+#                print "$storepath\n";
 
-                    # Construct a Nix expression that fetches and unpacks a
-                    # Nix archive from the network.
-                    my $fetch =
-                        "(import @datadir@/nix/corepkgs/fetchurl) " .
-                        "{url = $fullurl; md5 = \"$hash\"; system = \"@host@\"}";
-                    my $nixexpr =
-                        "((import @datadir@/nix/corepkgs/nar/unnar.nix) " .
-                        "{narFile = ($fetch); outPath = \"$storepath\"; system = \"@host@\"}) ";
-                    $fullexpr .= $nixexpr; # !!! O(n^2)?
+                # Construct a Nix expression that fetches and unpacks a
+                # Nix archive from the network.
+                my $fetch =
+                    "(import @datadir@/nix/corepkgs/fetchurl) " .
+                    "{url = $fullurl; md5 = \"$hash\"; system = \"@host@\"}";
+                my $nixexpr =
+                    "((import @datadir@/nix/corepkgs/nar/unnar.nix) " .
+                    "{narFile = ($fetch); outPath = \"$storepath\"; system = \"@host@\"}) ";
+                $fullexpr .= $nixexpr; # !!! O(n^2)?
 
-                    push @srcpaths, $storepath;
+                push @srcpaths, $storepath;
 
-                    foreach my $p (@preds) {
-                        push @sucs, $p;
-                        push @sucs, $storepath;
-                    }
+                foreach my $p (@preds) {
+                    push @sucs, $p;
+                    push @sucs, $storepath;
+                }
 
-                }
-                elsif (/^\s*StorePath:\s*(\/\S+)\s*$/) {
-                    $storepath = $1;
-                }
-                elsif (/^\s*NarName:\s*(\S+)\s*$/) {
-                    $narname = $1;
-                }
-                elsif (/^\s*MD5:\s*(\S+)\s*$/) {
-                    $hash = $1;
-                }
-                elsif (/^\s*SuccOf:\s*(\/\S+)\s*$/) {
-                    push @preds, $1;
-                }
-                else { die "bad line: $_"; }
             }
+            elsif (/^\s*StorePath:\s*(\/\S+)\s*$/) {
+                $storepath = $1;
+            }
+            elsif (/^\s*NarName:\s*(\S+)\s*$/) {
+                $narname = $1;
+                }
+            elsif (/^\s*MD5:\s*(\S+)\s*$/) {
+                $hash = $1;
+            }
+            elsif (/^\s*SuccOf:\s*(\/\S+)\s*$/) {
+                push @preds, $1;
+            }
+            else { die "bad line: $_"; }
         }
-
-        close MANIFEST;
     }
 
+    close MANIFEST;
+}
+
+
+# Obtain URLs either from the command line or from a configuration file.
+if (scalar @ARGV > 0) {
+    while (@ARGV) {
+        my $url = shift @ARGV;
+            processURL $url;
+    }
+} else {
+    open CONFFILE, "<$conffile";
+    while (<CONFFILE>) {
+        chomp;
+        if (/^\s*(\S+)\s*(\#.*)?$/) {
+            my $url = $1;
+            processURL $url;
+        }
+    }
+    close CONFFILE;
 }
 
 $fullexpr .= "]";