title: Android Debug Bridge (adb) command line tool exists in $PATH, but "command not found" in linux
body: <pre><code>sudo echo $PATH
  
  /usr/local/sbin:/usr/local/bin:/usr/sbin:/usr/bin:/sbin:/bin:/usr/games:/home/lubuntu/Tools/android-sdk-linux/platform-tools
  </code></pre>
  
  <p>adb exists in <code>/home/lubuntu/Tools/android-sdk-linux/platform-tools</code> </p>
  
  <p>Then I executed <code>adb start-server</code>:</p>
  
  <pre><code>* daemon not running. starting it now on port 5037 *
  * daemon started successfully *
  </code></pre>
  
  <p>Then <code>sudo adb install test.apk</code></p>
  
  <pre><code>sudo: adb: command not found
  </code></pre>
  
  <p>I have added adb in the environment variable $PATH, but sudo couldn't find it.
  Why?</p>