diff --git a/letsencrypt.sh b/letsencrypt.sh
index d276941..18a2619 100755
--- a/letsencrypt.sh
+++ b/letsencrypt.sh
@@ -145,7 +145,7 @@ init_system() {
 
 # Different sed version for different os types...
 _sed() {
-  if [ "${OSTYPE}" = "Linux" ]; then
+  if [[ "${OSTYPE}" = "Linux" ]]; then
     sed -r "${@}"
   else
     sed -E "${@}"
@@ -520,8 +520,6 @@ command_env() {
 
 # Main method (parses script arguments and calls command_* methods)
 main() {
-  OSTYPE="$(uname)"
-
   COMMAND=""
   set_command() {
     [[ -z "${COMMAND}" ]] || _exiterr "Only one command can be executed at a time. See help (-h) for more information."
@@ -633,6 +631,9 @@ main() {
   esac
 }
 
+# Determine OS type
+OSTYPE="$(uname)"
+
 # Check for missing dependencies
 check_dependencies