Or you could switch your shell to bash if that's what you'd prefer: % chsh -s /bin/bash You should be able to add that command to an appropriate shell startup script so that it's invoked every time (putting it in ~/.zlogin worked for me). To disable this feature, unset the 'zle_bracketed_paste' environment variable: % unset zle_bracketed_paste It's this 'zsh line editing bracketed paste' that's highlighting your text.
Zsh has a feature called 'bracketed paste' that allows the shell, specifically the zsh's line-editing mode known as 'zle', to handle pasted text differently than if the same text had been typed in one character at a time, assuming your terminal emulator supports it, which macOS's built-in Terminal.app does. As of macOS Catalina, the default shell for new accounts is now zsh instead of bash.
