title: Incomplete output on os/exec when executing psql commands
body: <p>I'm currently using <code>os/exec</code> to run many <code>psql</code> commands in sequence.</p>
  
  <p>My problem is that if there's an error during the execution of the script, the output doesn't show it. </p>
  
  <p>Example: 
  When executing the command file from the command line, the output is this:</p>
  
  <pre><code>SET
  CREATE FUNCTION
  psql:update-14.3.7.1/dml/----------------xxxxxxxx.sql:33: ERROR:  null value in column "tipoxxxxxxxx" violates not-null constraint
  DETALHE:  Failing row contains (9, 0, null, null, null, null, AAAAAAAAA_BBBBBBBBBB_CCCCC_BANANA, null, null, null).
  CONTEXTO:  SQL statement "insert INTO ----------------xxxxxxxx
          (id,versao,tipoxxxxxxxx,carrotdeapplefinal,carrotdetttttttt,ativa,funcionalidade,driver,alterar_na_xxxxxxxx)
          values
          (nextval('sq_----------------xxxxxxxx'),0,tipoaaaaaaaaa,carrotapple,carrottttttttt,alterarNaxxxxxxxx)"
  PL/pgSQL function createorupdateaaaaaaaaa() line 22 at SQL statement
  DROP FUNCTION
  </code></pre>
  
  <p>And executing the exact same file from the Go code, the output is:</p>
  
  <pre><code>SET
  CREATE FUNCTION
  DROP FUNCTION
  </code></pre>
  
  <p>My Go code for running commands(and showing the output) is:</p>
  
  <pre><code>    cmd := exec.Command(comando, argList...)
      var out bytes.Buffer
      var stderr bytes.Buffer
      cmd.Stdout = &amp;out
      cmd.Stderr = &amp;stderr
      err := cmd.Run()
      cmdS := out.String()
      fmt.Println("cmdS", cmdS)
      if err != nil {
          fmt.Println("XYZ")
          fmt.Println(fmt.Sprint(err) + ": " + stderr.String())
      }
  </code></pre>
  
  <p>How to modify my code to show the other lines of the output?</p>