In case you have uploaded some files to your OwnCloud, no matter how, but they not showing up in the browser, check that you include the following config parameter in your <owncloud root>/config/config.php file.

‘filesystem_check_changes’ => 1


You can also trigger a file scan by using the following commands.

File scans can be performed per-user, for a space-delimited list of users, for groups of users, and for all users.

sudo -u www-data php occ files:scan –all

sudo -u www-data php occ files:scan <username>

Source: https://doc.owncloud.com/server/next/admin_manual/configuration/server/occ_command.html





Links

Define how often filesystem changes are detected
https://doc.owncloud.com/server/next/admin_manual/configuration/server/config_sample_php_parameters.html#define-how-often-filesystem-changes-are-detected

The files:scan command
https://doc.owncloud.com/server/next/admin_manual/configuration/server/occ_command.html

Config.php Parameters
https://doc.owncloud.com/server/next/admin_manual/configuration/server/config_sample_php_parameters.html