diff --git a/Makefile b/Makefile
index 2c49549..a83d416 100644
--- a/Makefile
+++ b/Makefile
@@ -1,10 +1,14 @@
 frfac:
-	sed "1d;2i #!`./latest_perl`" frfac.in > frfac
+	sed '1s@^.*$$@\#\!'$$(latest_perl)@ frfac.in > frfac
 
 check:
 	`./latest_perl` -wc frfac.in
 	perlcritic frfac.in
-	ksh93 -n getviaphone
+	if which ksh93 > /dev/null 2>&1; then \
+		ksh93 -n getviaphone; \
+	else \
+		ksh -n getviaphone; \
+        fi
 
 install: frfac
 	sudo install -o root -g wheel -m 0755 -d /usr/local/bin