diff --git a/libozsh.zsh b/libozsh.zsh
index db13a46..8329078 100644
--- a/libozsh.zsh
+++ b/libozsh.zsh
@@ -50,7 +50,7 @@ function ozsh_update {
 }
 
 function ozsh_autoupdate {
-	timediff = $(( ($(date --date="$(date)" +%s) - $(date --date="$(cat $OZSH_LASTUPDATE_FILE)" +%s) ) / (60*60*24) ))
+	local timediff=$(( ($(date --date="$(date)" +%s) - $(date --date="$(cat $OZSH_LASTUPDATE_FILE)" +%s) ) / (60*60*24) ))
 	if [ $timediff -ge 7 ]; then
 		vared -p 'Would you like to update ozsh? [y/N]: ' -c answer
 		if [ "$answer" == "y" || "$answer" == "Y" ]; then