The version is shown in the footer at the bottom of each page....
As 'root'
(or, whichever user owns the subdirectories of /opt/atlassian/confluence)systemctl start confluence
As 'root'
(or, whichever user owns the subdirectories of /opt/atlassian/confluence)systemctl stop confluence
As 'root'
(or, whichever user owns the subdirectories of /opt/atlassian/confluence)systemctl status confluence
You can work out some key configuration information for a system where you don't already know this...
You just need to hunt for this... it's usually something like...
/opt/atlassian/confluence/current/confluence
View the confluence-init.properties file in WEB-INF/classes...
cat /opt/atlassian/confluence/current/confluence/WEB-INF/classes/confluence-init.properties
You should see a line like this...
confluence.home = /var/atlassian/application-data/confluence
View the file in your Local Home directory...
cat /var/atlassian/application-data/confluence/confluence.cfg.xml | grep hibernate.connection.password