diff --git a/src/channel/PhutilLogFileChannel.php b/src/channel/PhutilLogFileChannel.php
index 6607751..ecc9cc1 100644
--- a/src/channel/PhutilLogFileChannel.php
+++ b/src/channel/PhutilLogFileChannel.php
@@ -1,34 +1,41 @@
 <?php
 
 /**
  * A @{class:PhutilChannelChannel} which wraps some other channel and writes
  * data passed over it to a log file.
  */
 final class PhutilLogFileChannel extends PhutilChannelChannel {
 
   private $logfile;
 
   public function setLogfile($path) {
     $this->logfile = fopen($path, 'a');
     $this->log('--- '.getmypid().' ---');
     return $this;
   }
 
   public function read() {
     $buffer = parent::read();
-    $this->log('>>> '.phutil_loggable_string($buffer));
+
+    if (strlen($buffer)) {
+      $this->log('>>> '.phutil_loggable_string($buffer));
+    }
+
     return $buffer;
   }
 
   public function write($message) {
-    $this->log('<<< '.phutil_loggable_string($message));
+    if (strlen($message)) {
+      $this->log('<<< '.phutil_loggable_string($message));
+    }
+
     return parent::write($message);
   }
 
   private function log($message) {
     if ($this->logfile) {
       fwrite($this->logfile, $message."\n");
     }
   }
 
 }