在 Mac 上从终端运行 IRB 时出错 - 找不到 gem

Question

当我在终端中输入 irb 时，我得到的是：

Traceback (most recent call last):
    2: from /usr/local/opt/ruby/bin/irb:23:in `<main>'
    1: from /usr/local/lib/ruby/site_ruby/2.6.0/rubygems.rb:302:in `activate_bin_path'
/usr/local/lib/ruby/site_ruby/2.6.0/rubygems.rb:283:in `find_spec_for_exe': can't find gem irb (>= 0.a) with executable irb (Gem::GemNotFoundException)

我认为这可能与 gem 库或版本有关，但无法弄清楚。我是新手，不想进一步搞砸，任何帮助将不胜感激！提前致谢！