title: Is there a way to add or update file in tar.gz(tgz) without decompress?
body: <p>I'm looking for a way to update tgz file.
  I know what I can update tgz file by unzipping it, inserting file in directory and re-compressing it.
  But I do not want decompressed file was created in my disc.</p>
  <p>Tar has 'r' option(--append) what appending files to the end of an archive but when I use tar with 'r' option, console logged 'cannot update compressed archive.', 'Error is not recoverable: exiting now.'</p>
  <p>If it is impossible, I cannot help but if there is a way, plz let me know.</p>
  <p>I modified my question according to Basile Starynkevitch's comment.</p>
  <p>This is command for testing.</p>
  <pre><code>tar -rf myComppressedFile.tgz insert.txt
  </code></pre>
  <p>Result</p>
  <pre><code>tar: Cannot update compressed archives
  tar: Error is not recoverable: exiting now
  </code></pre>
  <p>vim myCompressedFile.tgz</p>
  <pre><code>./file1.txt
  ./file2.txt
  ./file3.txt
  ./directory1/
  ./directory1/file4.txt
  </code></pre>
  <p>what I want to update</p>
  <pre><code>./file1.txt
  ./file2.txt
  ./file3.txt
  ./directory1/
  ./directory1/file4.txt
  ./insert.txt &lt;&lt;&lt;&lt; I want to add like this file
  </code></pre>
  <p>My tgz file is about more 100 megabytes.</p>