I had to basically wipe my Mac and reinstall Catalina[1] because I messed up some python package installations very badly, and I was able to erase it seemingly successfully. There's only one primary odd change: my terminal changed its display. It now prompts me: "[lastname]@[firstname]s-MBP ~ %" where [firstname] and [lastname] are my first and last name [2]. (There are some other odd changes as well, like Google seems to take longer to respond, but that may be because of higher internet traffic.) After searching, I haven't found anyone with a similar issue.

Is this a signal that I messed something up while erasing my old system, or is this normal variance across machines? If it is an issue, what might it be, and how might I fix it?

Thank you!

[1] Following the instructions at https://support.apple.com/en-us/HT201065

[2] It used to be something more conventional, ending with $.

  • My terminal shell uses a %. Perhaps you changed the default shell and forgot. You can change the default shell using chsh. Apr 7, 2020 at 10:05
  • Had you upgraded to Catalina before? If so your shell would be bash as it was used in old macOS versions and maintained when upgrading. When you reinstall Catalina though you get the new default shell zsh. You can customize what the shell prompt looks like as described here: Customizing the zsh Prompt
    – lx07
    Apr 7, 2020 at 12:31

1 Answer 1


With MacOS Catalina, the default terminal shell switched from bash to zsh. It didn't migrate existing users, but when you reinstalled Catalina it took the opportunity to update your default. The default prompt for bash is '$', for zsh '%'. Use chsh -s /bin/bash to switch back to your old shell as default. Alternatively, change your prompt by setting the variable PS1. Note that if you stick with zsh, there are some changes like different auto-completion methods. Also, if you had any sourcing files for bash (like ~/.bash_profile or ~/.bashrc), you might have to update them to their zsh equivalents.

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