diff --git a/install.sh b/install.sh
index 7035d68..08f41db 100755
--- a/install.sh
+++ b/install.sh
@@ -1,12 +1,12 @@
-#!/bin/bash
+#!/bin/sh
 # This loads SCM Breeze into the shell session.
-exec_string='[[ -s "$HOME/.scm_breeze/scm_breeze.sh" ]] && . "$HOME/.scm_breeze/scm_breeze.sh"'
+exec_string='[ -s "$HOME/.scm_breeze/scm_breeze.sh" ] && . "$HOME/.scm_breeze/scm_breeze.sh"'
 
 # Add line to bashrc and zshrc if not already present.
 for rc in bashrc zshrc; do
-  if [[ -s "$HOME/.$rc" ]] && ! grep -q "$exec_string" "$HOME/.$rc"; then
-    echo -e "\n$exec_string" >> "$HOME/.$rc"
-    echo "== Added SCM Breeze to '~/.$rc'"
+  if [ -s "$HOME/.$rc" ] && ! grep -q "$exec_string" "$HOME/.$rc"; then
+    printf "\n$exec_string\n" >> "$HOME/.$rc"
+    printf "== Added SCM Breeze to '~/.$rc'\n"
   fi
 done