PHP Artisan Tinker crashing from any command

If you don't have the pcntl extension installed, try creating a config file at ~/.config/psysh/config.php if not already there:

<?php
return [
  'usePcntl' => false,
]; 

Source: https://github.com/bobthecow/psysh/issues/540#issuecomment-446480753

This happens on Mojave when you upgrade/install PHP 7.3 using homebrew, (It's a problem with PsySh (used by Tinker) and Homebrew's PHP 7.3.0 build.)

Simple solution is, In your php.ini set

pcre.jit=0

---

If you don't know which ini file is used, you can run php --ini to find it,

# /usr/local/etc/php/7.3/php.ini
- ;pcre.jit=1
+ pcre.jit=0