diff --git a/fact/GNUmakefile b/fact/GNUmakefile
new file mode 100644
index 0000000..13d48f3
--- /dev/null
+++ b/fact/GNUmakefile
@@ -0,0 +1,30 @@
+include GNUmakevars
+
+CONFDIR=../../configure
+
+all: configure fact
+
+clean:
+	rm fact customize
+
+install: $(BINDIR) $(BINDIR)/fact
+
+%: %.pl customize
+	sh ./customize < $< > $@
+	chmod +x $@
+
+%: %.sh customize
+	sh ./customize < $< > $@
+	chmod +x $@
+
+customize: configure
+	sh ./configure
+
+configure: $(CONFDIR)/start $(CONFDIR)/perl $(CONFDIR)/finish
+	cat $^ > $@
+
+$(BINDIR):
+	mkdir -p $@
+
+include GNUmakerules
+
diff --git a/fact/configure b/fact/configure
new file mode 100644
index 0000000..6fea68e
--- /dev/null
+++ b/fact/configure
@@ -0,0 +1,34 @@
+#!/bin/sh
+#
+echo "#!/bin/sh" > customize.$$
+echo "sed \\" > customize.$$
+chmod +x customize.$$
+
+################################################################
+# find a working perl:
+#
+for i in /usr/bin/perl /usr/local/bin/perl /usr/bin/perl5 /usr/local/bin/perl5
+do
+    if $i -e 'exit ($] < 5.000)'
+    then
+	echo $i works
+	perl="$i"
+	break
+    fi
+done
+if [ -z "$perl" ]
+then
+    could not find a working perl command, sorry.
+    exit 1
+fi
+echo "  -e 's,@@@perl@@@,$perl,g' \\" >> customize.$$
+
+
+################################################################
+# finish
+#	Add trailing newline and rename temp file to final name
+#
+echo  >> customize.$$
+
+mv customize.$$ customize
+
diff --git a/fact/fact.pl b/fact/fact.pl
new file mode 100644
index 0000000..ca83a85
--- /dev/null
+++ b/fact/fact.pl
@@ -0,0 +1,31 @@
+#!@@@perl@@@ -w
+use strict;
+
+sub usage {
+    print STDERR "Usage: $0 number\n";
+    exit(1);
+}
+
+sub fact {
+    my ($n) = @_;
+
+    my $d = 2;
+
+    my @f = ();
+
+    while ($d <= $n) {
+	if ($n % $d == 0) {
+	    push (@f, $d);
+	    $n /= $d;
+	} else {
+	    $d++;
+	}
+    }
+    return @f;
+}
+
+if (@ARGV != 1) { usage(); }
+my @f = fact($ARGV[0]);
+print "@f\n";
+
+#vim:sw=4