title: Start psql with read-only transactions by default
body: <p>My goal is to start the psql client with read-only transactions as the default.  I can get this behaviour my manually setting <a href="http://www.postgresql.org/docs/9.2/static/runtime-config-client.html#GUC-DEFAULT-TRANSACTION-READ-ONLY" rel="nofollow"><code>default_transaction_read_only</code></a> once psql has started (e.g. <code>SET default_transaction_read_only TO on</code>), but I don't want to have to do that.</p>
  
  <p>Theoretically this seems like it should work:</p>
  
  <pre><code>psql --set=default_transaction_read_only=on mydb myuser
  </code></pre>
  
  <p>But it doesn't, probably due to the caveat mentioned <a href="http://www.postgresql.org/docs/9.2/static/app-psql.html" rel="nofollow">here</a>:</p>
  
  <blockquote>
    <p>These assignments are done during a very early stage of start-up, so
    variables reserved for internal purposes might get overwritten later.</p>
  </blockquote>
  
  <p>Is there a way to do this, ideally with a single command line invocation?</p>