Convert to lowercase, then match.

autoattach

@@ -42,7 +42,8 @@ function attach_session
 		echo "There is no tmux session '$1'"
 		if [ -z "${AUTO_CREATE}" ]; then
       read -p "Do you want me to auto create sessions by default? [Y/n]: "
-            if [ "${REPLY}" = "y" -o -z "${REPLY}" ]; then
+      # convert to lowercase, then match
+      if [ "${REPLY,,}" = "y" -o -z "${REPLY}" ]; then
         write_setting 'AUTO_CREATE' '1'
         AUTO_CREATE=1
       else
@@ -54,6 +55,7 @@ function attach_session
       tmux new-session -s $1 2> /dev/null
       exit 0
     fi
+
     echo 'Nothing to do, exiting...'
     exit 1