How to Find Files by Group Ownership in Ubuntu Linux (find -group)

The Permission Structure

In Ubuntu Linux, file ownership is divided into two distinct categories: the specific User who owns the file, and the Group that owns the file. Groups are essential for allowing multiple different users (like a team of web developers) to edit the exact same set of files without sharing a single login. If you are auditing a shared server or attempting to diagnose permission errors for a web application, you cannot just search for files owned by a specific user. You must instruct the search engine to filter files based entirely on their assigned Group.

Using the find Command with -group

The Linux find command utilizes the -group flag to isolate files and directories that belong to a specific permission group.

1. Open your Terminal application (Ctrl + Alt + T) or log into your server via SSH.
2. To search the entire /var/www/ directory specifically for files that are owned by the www-data group (the default group for Apache/Nginx web servers), type the following command exactly:

   sudo find /var/www/ -group www-data

3. Press Enter and provide your administrator password.

Finding Orphaned Files

If an administrator deletes a Group from the Linux server without deleting the files owned by that group first, those files become “orphaned.” They still technically belong to a group ID, but that ID no longer exists in the system registry, which can cause severe security and execution errors. To find these highly specific broken files, you can use the -nogroup flag (e.g., sudo find / -nogroup). This forces the engine to scan the entire hard drive and output a list of any files belonging to a ghost group, allowing you to quickly reassign them.