diff --git a/tools/install.sh b/tools/install.sh
index e8f2612..89b5b39 100755
--- a/tools/install.sh
+++ b/tools/install.sh
@@ -12,7 +12,7 @@
 
 set -e
 
-if [ $UID == 0 ]; then CMD_PREFIX="sudo"; else CMD_PREFIX=""; fi
+if [ "$UID" = "0" ]; then CMD_PREFIX="sudo"; else CMD_PREFIX=""; fi
 
 if [ "$SHELL" != "$(which zsh)" ]; then
 	echo "$(which zsh)"