Find file owned by a group

find directory-location -group {group-name} -name {file-name}

directory-location : directory path.
-group {group-name} : group-name.
-name {file-name} : The file name or a search pattern

Issue: Plesk server will not allow updating plugins and the site is running as fastcgi – which uses the ftp user as the root user ( coldriverw:psacln) is the user:group for this account.

In this example, locate or find all files belongs to a group called “apache” in the /var/www/vhosts/coldriverdata.com/httpdocs/ directory:

[root@austin plugins]# find /var/www/vhosts/domain.com/httpdocs/ -group apache
/var/www/vhosts/domain.com/httpdocs/.htaccess
/var/www/vhosts/domain.com/httpdocs/wp-content/plugins/enhanced-tooltipglossary
/var/www/vhosts/domain.com/httpdocs/wp-content/plugins/enhanced-tooltipglossary/readme.txt

Change the files to the correct user:

 [root@austin plugins]# chown -R domain:psacln /var/www/vhosts/domain.com/httpdocs/wp-content

Retry the wordpress upload

Update Plugin
Downloading update from https://downloads.wordpress.org/plugin/enhanced-tooltipglossary.zip…

Unpacking the update…

Installing the latest version…

Removing the old version of the plugin…

Plugin updated successfully.

More information:
http://www.cyberciti.biz/faq/how-do-i-find-all-the-files-owned-by-a-particular-user-or-group/