Reading direct from TTY is needed when installing with cURL.

install.sh

@@ -7,7 +7,7 @@ pushd `git rev-parse --git-dir`/hooks > /dev/null
 
 if [ -f post-commit ] || [ -L post-commit ]; then
     echo "A post-commit file already exists."
-    read -p "Overwrite? [y/N] " -n 1 -r
+    read -p "Overwrite? [y/N] " -n 1 -r < /dev/tty
     echo
     if [[ ! $REPLY =~ ^[Yy]$ ]]; then
         exit 1