How to gracefully restart a process?

Firefox lacks a restart command — I want to to restart overnight since this is mandatory after updates (I automate security updates) and at least some addons (uBlock Origin) require a browser restart when patched.

Is the following command perfectly safe and sensible enough?[¹]

killall -s SIGTERM firefox ; firefox
  • Can killall firefox realistically hit non-Firefox processes?[²]
  • Is there a point in adding sleep between the shutdown and start? Will the system wait for all firefox processes to exit?

I’ll run the command in cron for now (with which I have basic experience).

[¹]: "default settings" is my secondary profile
[²] assuming that only official Fedora repos are used

I removed the secondary profile from the question, I couldn’t get both to launch simultaneously.

&& firefox -P "default settings"