diff --git a/HowtoRails.md b/HowtoRails.md
index 48760c00..200f9ff6 100644
--- a/HowtoRails.md
+++ b/HowtoRails.md
@@ -331,7 +331,7 @@ rails_env = `head -1 $(HOME}/www/current/config/database.yml | tr ':' ' '`
 # apt install rbenv ruby-build libssl-dev
 
 $ eval "$(rbenv init -)"
-$ rbenv install 2.4.0
+$ TMPDIR=~/tmp rbenv install 2.4.0
 $ rbenv global 2.4.0
 $ gem install bundle