title: What characters are not allowed in the rpm "Release" ?
body: <p>Machine 1</p>
  
  <pre><code>#uname -r
  Machine 1:3.2.45-0.6.wd.561.41.269.metal1.x86_64
  #rpmbuild --version
  RPM version 4.8.0
  </code></pre>
  
  <p>While trying rpmbuild I encountered 
  Illegal char ''' in: Release: 25.'4283295'.mybranch</p>
  
  <p>There was error in the script I wrote which appended the quotes around the number. </p>
  
  <p>On machine 2</p>
  
  <pre><code># uname -r
  2.6.16.33-xenU
  # rpmbuild --version
  RPM version 4.4.2
  </code></pre>
  
  <p>Here rpmbuild seemed to work with single quoted number in the name:
  myapp-1.4.25.'4283295'.mybranch.x86_64.rpm</p>
  
  <p>I gathered that single quote is not allowed in the Release in the earlier case.
  What is the set of characters that I should always avoid ?</p>
  
  <p>Are there differences due to the rpmbuild version ?</p>
  
  <p>I failed to find allowed characters in the rpm name/version/release.
  any pointers will be much appreciated. </p>