Fix bug in db3ad8a

Closes #7367

README.md

@@ -1221,7 +1221,7 @@ To activate authentication with the `.netrc` file you should pass `--netrc` to y
 
 The default location of the .netrc file is `~` (see below).
 
-As an alternative to using the `.netrc` file, which has the disadvantage of keeping your passwords in a plain text file, you can configure a custom shell command to provide the credentials for an extractor. This is done by providing the `--netrc-cmd` parameter, it shall output the credentials in the netrc format and return `0` on success, other values will be treated as an error. `{}` in the command will be replaced by the name of the extractor to make it possible to select the credentials for the right extractor (To use literal braces, double them like `{{}}`).
+As an alternative to using the `.netrc` file, which has the disadvantage of keeping your passwords in a plain text file, you can configure a custom shell command to provide the credentials for an extractor. This is done by providing the `--netrc-cmd` parameter, it shall output the credentials in the netrc format and return `0` on success, other values will be treated as an error. `{}` in the command will be replaced by the name of the extractor to make it possible to select the credentials for the right extractor.
 
 E.g. To use an encrypted `.netrc` file stored as `.authinfo.gpg`
 ```

yt_dlp/extractor/common.py

@@ -1297,8 +1297,9 @@ def _html_search_regex(self, pattern, string, name, default=NO_DEFAULT, fatal=Tr
     def _get_netrc_login_info(self, netrc_machine=None):
         netrc_machine = netrc_machine or self._NETRC_MACHINE
 
-        cmd = self.get_param('netrc_cmd', '').format(netrc_machine)
+        cmd = self.get_param('netrc_cmd')
         if cmd:
+            cmd = cmd.replace('{}', netrc_machine)
             self.to_screen(f'Executing command: {cmd}')
             stdout, _, ret = Popen.run(cmd, text=True, shell=True, stdout=subprocess.PIPE)
             if ret != 0: