Terminal is unable to quit /Cant install Homebrew

Your shell script login is messed up somewhere, as something is invoking the cat command to display the contents of some file.

Launch Finder, and go to your home directory if not already there, then press Command-Shift-Period (⌘⇧.) to toggle the hidden-file display setting. With hidden files viewable, look for and rename (.zlogin to .zlogin-save or whatever) any of the following list of files found there:

• .zlogin
• .zlogout
• .zprofile
• .zshenv
• .zshrc

Above assumes your login shell is zsh, and not bash. (System Preferences ? Users & Groups > Click the padlock and authenticate > Control-Click on your username at the top of the left column and select Advanced Options from the popup menu. Make no changes here, just check that your login shell is /bin/zsh and not not /bin/bash. If this is that bash you're still using, post back and I'll post the bash shell equivalents to the above zsh files.

Then you get to untangle whatever happened here with Homebrew.

When trying to resolve this, it would have been better to revert to a Time Machine backup immediately prior to the Homebrew issue rather than to move forward with upgrades, but we are where we are.