diff --git a/switch-ffi.sh b/switch-ffi.sh
index fa1ca27..221fe92 100755
--- a/switch-ffi.sh
+++ b/switch-ffi.sh
@@ -1,5 +1,6 @@
 #!/bin/sh
-
-perl -pi -e "s/^package cwtch/\/\/package cwtch/" lib.go
-perl -pi -e "s/^\/\/package main/package main/" lib.go
-perl -pi -e "s/^\/\/func main\(\)/func main\(\)/" lib.go
+# using '-i.bak' and 'rm .bak' for gnu sed (linux) and bsd sed (macosx) compat
+sed -i.bak "s/^package cwtch/\/\/package cwtch/" lib.go
+sed -i.bak "s/^\/\/package main/package main/" lib.go
+sed -i.bak "s/^\/\/func main()/func main()/" lib.go
+rm lib.go.bak
diff --git a/switch-gomobile.sh b/switch-gomobile.sh
index afb97d5..f89c584 100755
--- a/switch-gomobile.sh
+++ b/switch-gomobile.sh
@@ -1,5 +1,6 @@
 #!/bin/sh
-
-perl -pi -e "s/^\/\/package cwtch/package cwtch/" lib.go
-perl -pi -e "s/^package main/\/\/package main/" lib.go
-perl -pi -e "s/^func main\(\)/\/\/func main\(\)/" lib.go
+# using '-i.bak' and 'rm .bak' for gnu sed (linux) and bsd sed (macosx) compat
+sed -i.bak "s/^\/\/package cwtch/package cwtch/" lib.go
+sed -i.bak "s/^package main/\/\/package main/" lib.go
+sed -i.bak "s/^func main()/\/\/func main()/" lib.go
+rm lib.go.bak