pod install Library not loaded:

执行

 pod install

出现一下错误

/Users/tanhuang/.rvm/rubies/ruby-2.3.0/lib/ruby/site_ruby/2.3.0/rubygems/core_ext/kernel_require.rb:120:in `require': dlopen(/Users/tanhuang/.rvm/rubies/ruby-2.3.0/lib/ruby/2.3.0/x86_64-darwin16/digest/sha2.bundle, 9): Library not loaded: /usr/local/opt/openssl/lib/libcrypto.1.0.0.dylib (LoadError)
  Referenced from: /Users/tanhuang/.rvm/rubies/ruby-2.3.0/lib/ruby/2.3.0/x86_64-darwin16/digest/sha2.bundle
  Reason: image not found - /Users/tanhuang/.rvm/rubies/ruby-2.3.0/lib/ruby/2.3.0/x86_64-darwin16/digest/sha2.bundle
    from /Users/tanhuang/.rvm/rubies/ruby-2.3.0/lib/ruby/site_ruby/2.3.0/rubygems/core_ext/kernel_require.rb:120:in `require'
    from /Users/tanhuang/.rvm/rubies/ruby-2.3.0/lib/ruby/2.3.0/digest/sha2.rb:14:in `<top (required)>'
    from /Users/tanhuang/.rvm/rubies/ruby-2.3.0/lib/ruby/site_ruby/2.3.0/rubygems/core_ext/kernel_require.rb:120:in `require'
    from /Users/tanhuang/.rvm/rubies/ruby-2.3.0/lib/ruby/site_ruby/2.3.0/rubygems/core_ext/kernel_require.rb:120:in `require'
    from /Users/tanhuang/.rvm/gems/ruby-2.3.0@global/gems/typhoeus-1.3.1/lib/typhoeus.rb:1:in `<top (required)>'
    from /Users/tanhuang/.rvm/rubies/ruby-2.3.0/lib/ruby/site_ruby/2.3.0/rubygems/core_ext/kernel_require.rb:68:in `require'
    from /Users/tanhuang/.rvm/rubies/ruby-2.3.0/lib/ruby/site_ruby/2.3.0/rubygems/core_ext/kernel_require.rb:68:in `require'
    from /Users/tanhuang/.rvm/gems/ruby-2.3.0@global/gems/cocoapods-1.9.1/lib/cocoapods/sources_manager.rb:5:in `<top (required)>'
    from /Users/tanhuang/.rvm/rubies/ruby-2.3.0/lib/ruby/site_ruby/2.3.0/rubygems/core_ext/kernel_require.rb:68:in `require'
    from /Users/tanhuang/.rvm/rubies/ruby-2.3.0/lib/ruby/site_ruby/2.3.0/rubygems/core_ext/kernel_require.rb:68:in `require'
    from /Users/tanhuang/.rvm/gems/ruby-2.3.0@global/gems/cocoapods-1.9.1/lib/cocoapods/core_overrides.rb:1:in `<top (required)>'
    from /Users/tanhuang/.rvm/rubies/ruby-2.3.0/lib/ruby/site_ruby/2.3.0/rubygems/core_ext/kernel_require.rb:68:in `require'

感觉是ruby版本过低
升级一下ruby

先获取一下ruby版本列表

rvm list known

[ruby-]1.8.6[-p420]
[ruby-]1.8.7[-head] # security released on head
[ruby-]1.9.1[-p431]
[ruby-]1.9.2[-p330]
[ruby-]1.9.3[-p551]
[ruby-]2.0.0[-p648]
[ruby-]2.1[.10]
[ruby-]2.2[.10]
[ruby-]2.3[.8]
[ruby-]2.4[.10]
[ruby-]2.5[.8]
[ruby-]2.6[.6]
[ruby-]2.7[.2]
[ruby-]3[.0.0]

在执行

rvm install 2.5.8

执行完成完成之后，可以先查看一下本地所有ruby版本

rvm list

=* ruby-2.3.0 [ x86_64 ]
   ruby-2.5.8 [ x86_64 ]

目前默认版本是2.3.0
需要更换一下默认版本

rvm use 2.5.6 --default

更新成功

ruby-2.3.0 [ x86_64 ]
=*  ruby-2.5.8 [ x86_64 ]

最后再执行一下

pod install

终于解决了

ps：记录一下，好几个项目都遇到这个情况了。