diff --git a/README.markdown b/README.markdown
index 00937c0..6fba0bf 100644
--- a/README.markdown
+++ b/README.markdown
@@ -184,7 +184,7 @@ Nota bene: Avoid running nvm while the tests are running.
 
 To activate, you need to source `bash_completion`:
 
-  	[[ -r $NVM_DIR/bash_completion ]] && . $NVM_DIR/bash_completion
+  	[ -r "$NVM_DIR/bash_completion" ] && . "$NVM_DIR/bash_completion"
 
 Put the above sourcing line just below the sourcing line for NVM in your profile (`.bashrc`, `.bash_profile`).