title: An appendable compressed archive
body: <p>I have a requirement to maintain a compressed archive of log files.  The log filenames are unique and the archive, once expanded, is simply one directory containing all the log files.</p>
  
  <p>The current solution isn't scaling well, since it involves a gzipped tar file.  Every time a log file is added, they first decompress the entire archive, add the file, and re-gzip.  </p>
  
  <p>Is there a Unix archive tool that can add to a compressed archive without completely expanding and re-compressing?  Or can gzip perform this, given the right combination of arguments?</p>