Update docstring for GPG.encrypt_file().

gnupg/gnupg.py

@@ -788,7 +788,36 @@ class GPG(object):
     def encrypt_file(self, file, recipients, sign=None,
                      always_trust=False, passphrase=None,
                      armor=True, output=None, symmetric=False):
-        """Encrypt the message read from the file-like object :param:file ."""
+        """Encrypt the message read from ``file``.
+
+        :type file: file or :class:BytesIO
+        :param file: The file or bytestream to encrypt.
+        :type recipients: str or list or tuple
+        :param recipients: The recipients to encrypt to. Recipients may be
+                           specified by UID or keyID/fingerprint.
+        :param str sign: The keyID to use for signing, i.e.
+                         "gpg --sign --default-key A3ADB67A2CDB8B35 ..."
+        :param bool always_trust: If True, ignore trust warnings on recipient
+                                  keys. If False, display trust warnings.
+                                  (default: False)
+        :param bool passphrase: If True, use the stored passphrase for our
+                                secret key.
+
+        :param bool armor: If True, ascii armor the encrypted output; if False,
+                           the encrypted output will be in binary
+                           format. (default: True)
+
+        :param str output: The output file to write to. If not specified, the
+                           encrypted output is returned, and thus should be
+                           stored as an object in Python. For example:
+
+        >>> gpg = gnupg.GPG(gpghome='./tmp_test')
+
+        """
+        if output:  # write the output to a file with the specified name
+            if os.path.exists(output):
+                os.remove(output) # to avoid overwrite confirmation message
+            args.append('--output "%s"' % output)
         args = ['--encrypt']
         if symmetric:
             args = ['--symmetric']