How to apply a patch to a Drupal module
Following the Drupal documentation on applying patches.
The module localization client, originally developed for Drupal 6, needs a patch to the Drupal core module, locale (note that while locale is core it is also optional and disabled by default).
In this case the patch lives in the l10n_client module's directory, which Agaric (against standard and best practices) keeps in modules/contributed. The patch was also not made relative to the Drupal root directory, although it could have been as locale is a core module.
patch < ../contributed/l10n_client/locale_module.patch
If that gives you an error like
-bash: patch: command not found
you probably need to install the patch utility first, which, if you're on Debian or Ubuntu, you can do with this command:
aptitude install patch