How do I check if a module is being used by another?

Question

I'm using a multi-site setup with Drupal 7.14 core, and I want to disable some modules within my sites/all/modules shared folder. One of them in particular is the File_Entity module.

Is there a way (drush, programmatically, bash script, etc) to check if another module (e.g. Views, custom CCK) is using it? drush pml | grep File Entity only let me see what is enabled or disabled, not if it is currently in use, or safe to remove.

Answer 1

drush pm-info mymodule|grep "Required by"

grep or don't grep is up to you ;)

Beware this does not list fields that require the module. This implies to views that use fields too.

fields: admin/reports/fields

views: admin/reports/fields/views-fields

those will list fields only, so if you have special pagers, formatters or something else that come from a module you will still have to search for them.

Answer 2

There is no drush pm-info command in Drush 9.3, it was replaced pm:list.

(https://github.com/drush-ops/drush/issues/3487, https://github.com/drush-ops/drush/issues/5557)

But now there is no Required by field in a field list
(see FIELDS section in drush pm:list --help)

Current workaround is just open /admin/modules page and look for Required by,
or use some php code if you have access to the drush.

drush ev '$module = "views"; $modules = _system_rebuild_module_data(); \Drupal::moduleHandler()->buildModuleDependencies($modules); var_dump($modules[$module]->required_by);'

UPD: Drupal 9 version:

# Dependencies of the module
drush ev '$module = "views"; $modules = \Drupal::service("extension.list.module")->getList(); echo implode(array_keys($modules[$module]->requires),", ");'
# Dependencies to the module
drush ev '$module = "views"; $modules = \Drupal::service("extension.list.module")->getList(); echo implode(array_keys($modules[$module]->required_by),", ");'

NOTE: be worried with php code, may cause performance issues.