title: flutter doctor - CocoaPods installed but not working
body: <p>using zsh - use to work in bash<br />
  brew doctor - Your system is ready to brew.<br />
  flutter doctor gives this error</p>
  <pre><code>[!] Xcode - develop for iOS and macOS (Xcode 12.2)
      ✗ CocoaPods installed but not working.
          You appear to have CocoaPods installed but it is not working.
          This can happen if the version of Ruby that CocoaPods was installed with is different from the one being used to invoke it.
          This can usually be fixed by re-installing CocoaPods. For more info, see https://github.com/flutter/flutter/issues/14293.
        To re-install CocoaPods, run:
          sudo gem install cocoapods  
  </code></pre>
  <p>sudo gem install cocoapods</p>
  <pre><code>Gives this error  
  dyld: Library not loaded: /usr/local/opt/gmp4/lib/libgmp.3.5.2.dylib  
    Referenced from: /Users/puser/.rvm/rubies/ruby-2.5.1/bin/ruby  
    Reason: image not found  
  zsh: abort      sudo gem install cocoapods  
  </code></pre>
  <p><strong>I can't get this error above corrected - any suggestions?</strong></p>
  <p>which pod</p>
  <pre><code>/Users/puser/.rvm/rubies/ruby-2.5.1/bin/pod
  </code></pre>
  <p>which gem</p>
  <pre><code>gem () {
      \typeset result
      (
          \typeset rvmrc
          rvm_rvmrc_files=(&quot;/etc/rvmrc&quot; &quot;$HOME/.rvmrc&quot;) 
          if [[ -n &quot;${rvm_prefix:-}&quot; ]] &amp;&amp; ! [[ &quot;$HOME/.rvmrc&quot; -ef &quot;${rvm_prefix}/.rvmrc&quot; ]]
          then
              rvm_rvmrc_files+=(&quot;${rvm_prefix}/.rvmrc&quot;) 
          fi
          for rvmrc in &quot;${rvm_rvmrc_files[@]}&quot;
          do
              [[ -s &quot;${rvmrc}&quot; ]] &amp;&amp; source &quot;${rvmrc}&quot; || true
          done
          unset rvm_rvmrc_files
          command gem &quot;$@&quot;
      ) || result=$? 
      hash -r
      return ${result:-0}
  }
  </code></pre>
  <p>which ruby</p>
  <pre><code>/Users/puser/.rvm/rubies/ruby-2.5.1/bin/ruby
  </code></pre>