jekyll server运行报错

[HEXING19]

报错信息如下：
Traceback (most recent call last):
5: from /usr/local/bin/jekyll:23:in <main>' 4: from /usr/local/bin/jekyll:23:in load'
3: from /var/lib/gems/2.5.0/gems/jekyll-4.2.0/exe/jekyll:11:in <top (required)>' 2: from /var/lib/gems/2.5.0/gems/jekyll-4.2.0/lib/jekyll/plugin_manager.rb:50:in require_from_bundler'
1: from /usr/lib/ruby/2.5.0/rubygems/core_ext/kernel_require.rb:59:in require' /usr/lib/ruby/2.5.0/rubygems/core_ext/kernel_require.rb:59:in require': cannot load such file -- bundler (LoadError)