Bringing down my ZSH load times from ~3.1s to ~230ms
This year, the amount of time I spend in the terminal has gone significantly up thanks to Claude Code.
I got to a point where I couldn’t tolerate how slow opening a new shell session got. Naturally, I decided to fix it.
First, I needed to truly understand how slow my zsh was.
I ran time to get the exact load time of my zsh.
-i : interactive mode; needed to understand prompts, completions, aliases, etc. -l : login mode; needed to load /etc/zprofile and ~/.zprofile , etc.) in addition to .zshrc (I only use .zshrc and a ~/shell_overrides.sh file to load computer specific config) -c exit : run the exit command immediately and quit
These give you a true load time. The result didn’t come as a surprise.