title: What is the difference of sudo bash and sudo command in bash file?
body: <p>I would like to append some commands to ${HOME}/.bashrc file.</p>
  
  <p>I made a script to do it.</p>
  
  <pre><code># file name : setup_bash
  bashrc_path="${HOME}/.bashrc"
  comment="test"
  sudo echo "${comment}" &gt;&gt; "${bashrc_path}"
  </code></pre>
  
  <p>and run it by</p>
  
  <pre><code>bash setup_bash
  </code></pre>
  
  <p>And it results in an error.</p>
  
  <pre><code>setup_bash: line 19: /home/user/.bashrc: Permission denied
  </code></pre>
  
  <p>line 19 is at (sudo echo ...).</p>
  
  <p>Next I tried the following code,</p>
  
  <pre><code>sudo bash setup_bash
  </code></pre>
  
  <p>It results in success.</p>
  
  <p>What is the difference of them? Please teach me it.</p>