diff --git a/installer/nixos-hardware-scan.pl b/installer/nixos-hardware-scan.pl
new file mode 100644
index 000000000000..5b2f6692d865
--- /dev/null
+++ b/installer/nixos-hardware-scan.pl
@@ -0,0 +1,174 @@
+#! @perl@ -w
+
+use File::Spec;
+use File::Basename;
+
+
+my @kernelModules = ();
+my @initrdKernelModules = ();
+
+
+# Read a file, returning undef if the file cannot be opened.
+sub readFile {
+ my $filename = shift;
+ my $res;
+ if (open FILE, "<$filename") {
+ my $prev = $/;
+ undef $/;
+ $res = <FILE>;
+ $/ = $prev;
+ close FILE;
+ chomp $res;
+ }
+ return $res;
+}
+
+
+my $cpuinfo = readFile "/proc/cpuinfo";
+
+
+sub hasCPUFeature {
+ my $feature = shift;
+ return $cpuinfo =~ /^flags\s*:.* $feature( |$)/m;
+}
+
+
+# Detect the number of CPU cores.
+my $cpus = scalar (grep {/^processor\s*:/} (split '\n', $cpuinfo));
+
+
+# CPU frequency scaling. Not sure about this test.
+push @kernelModules, "acpi-cpufreq" if hasCPUFeature "acpi";
+
+
+# Virtualization support?
+push @kernelModules, "kvm-intel" if hasCPUFeature "vmx";
+push @kernelModules, "kvm-amd" if hasCPUFeature "svm";
+
+
+# Look at the PCI devices and add necessary modules. Note that most
+# modules are auto-detected so we don't need to list them here.
+# However, some are needed in the initrd to boot the system.
+
+sub pciCheck {
+ my $path = shift;
+ my $vendor = readFile "$path/vendor";
+ my $device = readFile "$path/device";
+ my $class = readFile "$path/class";
+
+ my $module;
+ if (-e "$path/driver/module") {
+ $module = basename `readlink -f $path/driver/module`;
+ chomp $module;
+ }
+
+ print "$path: $vendor $device $class";
+ print " $module" if defined $module;
+ print "\n";
+
+ if (defined $module) {
+ # See the bottom of http://pciids.sourceforge.net/pci.ids for
+ # device classes.
+ if (# Mass-storage controller. Definitely important.
+ $class =~ /^0x01/ ||
+
+ # Firewire controller. A disk might be attached.
+ $class =~ /^0x0c00/ ||
+
+ # USB controller. Needed if we want to use the
+ # keyboard when things go wrong in the initrd.
+ $class =~ /^0x0c03/
+ )
+ {
+ push @initrdKernelModules, $module;
+ }
+ }
+}
+
+foreach my $path (glob "/sys/bus/pci/devices/*") {
+ pciCheck $path;
+}
+
+
+# Idem for USB devices.
+
+sub usbCheck {
+ my $path = shift;
+ my $class = readFile "$path/bInterfaceClass";
+ my $subclass = readFile "$path/bInterfaceSubClass";
+ my $protocol = readFile "$path/bInterfaceProtocol";
+
+ my $module;
+ if (-e "$path/driver/module") {
+ $module = basename `readlink -f $path/driver/module`;
+ chomp $module;
+ }
+
+ print "$path: $class $subclass $protocol";
+ print " $module" if defined $module;
+ print "\n";
+
+ if (defined $module) {
+ if (# Mass-storage controller. Definitely important.
+ $class eq "08" ||
+
+ # Keyboard. Needed if we want to use the
+ # keyboard when things go wrong in the initrd.
+ ($class eq "03" && $protocol eq "01")
+ )
+ {
+ push @initrdKernelModules, $module;
+ }
+ }
+}
+
+foreach my $path (glob "/sys/bus/usb/devices/*") {
+ if (-e "$path/bInterfaceClass") {
+ usbCheck $path;
+ }
+}
+
+
+
+# Generate the configuration file.
+
+sub removeDups {
+ my %seen;
+ my @res = ();
+ foreach my $s (@_) {
+ if (!defined $seen{$s}) {
+ $seen{$s} = "";
+ push @res, $s;
+ }
+ }
+ return @res;
+}
+
+sub toNixExpr {
+ my $res = "";
+ foreach my $s (@_) {
+ $res .= " \"$s\"";
+ }
+ return $res;
+}
+
+my $initrdKernelModules = toNixExpr(removeDups @initrdKernelModules);
+my $kernelModules = toNixExpr(removeDups @kernelModules);
+
+
+print <<EOF ;
+# This is a generated file. Do not modify!
+# Make changes to /etc/nixos/configuration.nix instead.
+{
+ boot = {
+ initrd = {
+ extraKernelModules = [ $initrdKernelModules ];
+ };
+ kernelModules = [ $kernelModules ];
+ };
+
+ nix = {
+ maxJobs = $cpus;
+ };
+}
+EOF
diff --git a/installer/nixos-hardware-scan.sh b/installer/nixos-hardware-scan.sh
deleted file mode 100644
index 06fbb11dfa1f..000000000000
--- a/installer/nixos-hardware-scan.sh
+++ /dev/null
@@ -1,144 +0,0 @@
-#! @shell@ -e
-
-
-kernelModules=
-initrdKernelModules=
-
-hasCPUFeature() {
- local feature="$1"
- cat /proc/cpuinfo | grep -q "^flags.* $feature\( \|$\)"
-}
-
-needKernelModule() {
- kernelModules="$kernelModules \"$1\""
-}
-
-needInitrdKernelModule() {
- initrdKernelModules="$initrdKernelModules \"$1\""
-}
-
-
-# Detect the number of CPU cores.
-cpus="$(cat /proc/cpuinfo | grep '^processor' | wc -l)"
-
-
-# CPU frequency scaling. Not sure about this test.
-if hasCPUFeature "acpi"; then
- needKernelModule "acpi-cpufreq"
-fi
-
-
-# Virtualization support?
-if hasCPUFeature "vmx"; then
- needKernelModule "kvm-intel"
-fi
-
-if hasCPUFeature "svm"; then
- needKernelModule "kvm-amd"
-fi
-
-
-# Look at the PCI devices and add necessary modules. Note that most
-# modules are auto-detected so we don't need to list them here.
-# However, some are needed in the initrd to boot the system.
-
-pciCheck() {
- local path="$1"
- local vendor="$(cat $path/vendor)"
- local device="$(cat $path/device)"
- local class="$(cat $path/class)"
-
- local module
- if test -e "$path/driver/module"; then
- module=$(basename $(readlink -f $path/driver/module))
- fi
-
- echo "$path: $vendor $device $class $module"
-
- if test -n "$module"; then
- # See the bottom of http://pciids.sourceforge.net/pci.ids for
- # device classes.
- case $class in
- 0x01*)
- # Mass-storage controller. Definitely important.
- needInitrdKernelModule $module
- ;;
- 0x0c00*)
- # Firewire controller. A disk might be attached.
- needInitrdKernelModule $module
- ;;
- 0x0c03*)
- # USB controller. Needed if we want to use the
- # keyboard when things go wrong in the initrd.
- needInitrdKernelModule $module
- ;;
- esac
- fi
-}
-
-for path in /sys/bus/pci/devices/*; do
- pciCheck "$path"
-done
-
-
-# Idem for USB devices.
-
-usbCheck() {
- local path="$1"
- local class="$(cat $path/bInterfaceClass)"
- local subclass="$(cat $path/bInterfaceSubClass)"
- local protocol="$(cat $path/bInterfaceProtocol)"
-
- local module
- if test -e "$path/driver/module"; then
- module=$(basename $(readlink -f $path/driver/module))
- fi
-
- echo "$path: $class $subclass $protocol $module"
-
- if test -n "$module"; then
- # See http://www.linux-usb.org/usb.ids for
- # classes/subclasses/protocols.
- case $class:$subclass:$protocol in
- 08:*)
- # Mass-storage controller. Definitely important.
- needInitrdKernelModule $module
- ;;
- 03:*:01)
- # Keyboard. Needed if we want to use the
- # keyboard when things go wrong in the initrd.
- needInitrdKernelModule $module
- ;;
- esac
- fi
-}
-
-for path in /sys/bus/usb/devices/*; do
- if test -e "$path/bInterfaceClass"; then
- usbCheck "$path"
- fi
-done
-
-
-# Remove duplicate modules. !!! preserve order
-kernelModules=$(for i in $kernelModules; do echo $i; done | sort | uniq)
-initrdKernelModules=$(for i in $initrdKernelModules; do echo $i; done | sort | uniq)
-
-
-# Generation the configuration file.
-cat <<EOF
-# This is a generated file. Do not modify!
-# Make changes to /etc/nixos/configuration.nix instead.
-{
- boot = {
- initrd = {
- extraKernelModules = [ $(echo $initrdKernelModules) ];
- };
- kernelModules = [ $(echo $kernelModules) ];
- };
-
- nix = {
- maxJobs = $cpus;
- };
-}
-EOF