title: How to Install Android SDK commandline tool for Flutter upgrade error?
body: <p>How to install Android SDK commandline tool on a Ubuntu remote server which doesn't have Display/GUI.
  When I run, 'flutter upgrade' it gives me the below and I wanted to know if I can use Android SDK commandline tool for resolving the issue.</p>
  <pre><code>$flutter upgrade                                                                                
  Upgrading Flutter from /home/yvelumani/flutterDev/sdk/flutter...  
  Building flutter tool...`
  
  Upgrading engine...
  Downloading Android Maven dependencies...
  Failed to download the Android dependencies
  Downloading Android Maven dependencies...                         127.7s (!)
  
  Flutter 1.22.0-10.0.pre.133 • channel master • https://github.com/flutter/flutter.git  
  Framework • revision 577de1c44e (46 minutes ago) • 2020-09-10 15:55:03 -0700  
  Engine • revision fee6f9e533  
  Tools • Dart 2.10.0 (build 2.10.0-110.0.dev)
  
  Running flutter doctor...   
  Doctor summary (to see all details, run flutter doctor -v):  
  [✓] Flutter (Channel master, 1.22.0-10.0.pre.133, on Linux, locale en_US.UTF-8)  
  [!] Android toolchain - develop for Android devices   
      ✗ Unable to locate Android SDK.  
        Install Android Studio from: https://developer.android.com/studio/index.html  
        On first launch it will assist you in installing the Android SDK components.  
        (or visit https://flutter.dev/docs/get-started/install/linux#android-setup for detailed instructions).  
        If the Android SDK has been installed to a custom location, set ANDROID_HOME to that location.  
        You may also want to add it to your PATH environment variable.
  
      ✗ Android SDK file not found: adb.  
  [!] Android Studio (not installed)  
  [✓] Proxy Configuration  
  [!] Connected device  
      ! No devices available  
  
  ! Doctor found issues in 3 categories.
  </code></pre>
  <p>I have downloaded android SDK commandline tool from <a href="https://developer.android.com/studio#command-tools" rel="nofollow noreferrer">https://developer.android.com/studio#command-tools</a>. But I am not sure how to install this tool and what path to be chosen as ANDROID_HOME?</p>
  <p>NOTE: I am not going/able to use Android Studio for my app development.</p>
  <p>Thanks for the help in advance.</p>