title: echo $ANDROID_HOME returns blank (mac os catalina)
body: <p><a href="https://facebook.github.io/react-native/docs/getting-started" rel="noreferrer">I've followed the instructions here</a> to install android studio and the android sdk.</p>
  
  <p>I've added the following lines to ~/.bash_profile, and I've run source ~/.bash_profile.</p>
  
  <pre><code>export ANDROID_HOME=$HOME/Library/Android/sdk
  export PATH=$PATH:$ANDROID_HOME/emulator
  export PATH=$PATH:$ANDROID_HOME/tools
  export PATH=$PATH:$ANDROID_HOME/tools/bin
  export PATH=$PATH:$ANDROID_HOME/platform-tools
  </code></pre>
  
  <p>The path is correct, I've checked it in Android Studio > Preferences > System Settings > Android SDK.</p>
  
  <p>What is the problem? When I run source ~/.bash_profile, and then echo $ANDROID_HOME, I get some output. But if I close the terminal and restart it, and then I run echo $ANDROID_HOME, I get no output.</p>
  
  <p>If found similar questions here and on other websites, but nothing seems to work. Editing the export lines, directly executing "export ..." in the terminal instead of bash_profile, ... . It all fails to work.</p>
  
  <p>Anyone some tips to help me out?</p>