When I reconfigure my Zsh terminal, I want to see the changes immediately. A good way to do that on Mac is: exec zsh This uses the Zshbuiltin exec command to replace my login shell (Zsh) with another login shell (Zsh). Sourcing the Zsh config (source ~/.zshrc) is less reliable, as things like custom functions you’ve removed tend to stick around. Check out zshbuiltin for more.