The only time I've ever had shell startup time be significant is when loading fancy shell rc stuff (oh-my-zsh is the most infamous but there are many others) U

The only time I've ever had shell startup time be significant is when loading fancy shell rc stuff (oh-my-zsh is the most infamous but there are many others) Unfortunately I've hit some obscure bug with exactly when `HISTFILESIZE` is applied, and had some shells truncate all my history undesirably. There are also problems with reading history if the timestamp format changes.