Make sure dotfiles path of fish is set up correctly

fish/setup.sh

@@ -18,6 +18,10 @@ function main()
   # Install configuration files
   makedir ${HOME}/.config
 
+  if ! head -n 1 ${DOTFILES}/fish/config.fish | grep ${DOTFILES} >/dev/null; then
+    sed -i '' "1s;.*;set -x DOTFILES ${DOTFILES};" ${DOTFILES}/fish/config.fish
+  fi
+
   linkfile ${DOTFILES}/fish ${HOME}/.config/fish
 
   print_ok "Fish shell installed"