diff --git a/.config/fish/config.fish b/.config/fish/config.fish
index 93d1461..e95d3be 100644
--- a/.config/fish/config.fish
+++ b/.config/fish/config.fish
@@ -59,7 +59,7 @@ if status --is-interactive
     alias g="git"
 
     mkdir -p ~/.local
-    time_diff=(expr (date '+%s') - (cat "$HOME/.local/last_shell" 2>/dev/null || echo 0))
+    set time_diff (expr (date '+%s') - (cat "$HOME/.local/last_shell" 2>/dev/null || echo 0))
     if [ "$time_diff" -gt "28800" ] 
         [ -d "$HOME/tmp" ] && rm -rf "$HOME/tmp/*"
         git sit && date '+%s' > "$HOME/.local/last_shell"