What to do in case the psql command not found?

If psql command not found -

  Mac OS Big Sur:

Before installing zsh, bash was working perfectly fine. After switching from bash to zsh I experienced the infamous: command not found. I realise that my PATH was empty for this particular shell. in the terminal: env

  then copy the PATH line(s) (could be a multi line value!):PATH=/....

and in your personal directory: /Users/your_name/ you should find the .zshrc file. At the end of this file put:

  export PATH=/...

quit your terminal, launch it again and you should be good.