drush:tldr:e6c3f

The command "drush en ${foo}" is used in Drupal to enable a module with the name specified in the "${foo}" variable.

Here's how it works:

1. "drush" is a command-line tool used for managing Drupal installations. It provides various commands to perform common Drupal tasks.

2. "en" is short for "enable" and is a command in Drush used to enable a module.

3. "${foo}" is a placeholder variable. In the command, it represents the name of the module you want to enable. This variable needs to be replaced with the actual name of the module you want to enable. For example, if you want to enable the "views" module, you would replace "${foo}" with "views" like this: "drush en views".

By executing this command with the appropriate module name, Drush will enable that module in the Drupal installation.