title: Remove path from environment variables
body: <p>For mistake I have added a path that I don't want to use.<br>
  I have create a file named .base_profile, exported the path using the command source .base_profile, but I don't need this path, how to delete it?</p>
  
  <p>Maybe the title wasn't so appropriate, but I haven't modified the PATH variable.<br>
  I have written this in the .base_profile file:  </p>
  
  <pre><code>export MP=$MP/usr/local/mysql/bin
  </code></pre>
  
  <p>And then used the source command.The problem is with the MP variable, which is not one that I want, it's too long.I want to delete it, how to do it?</p>