The file /data/project/alvaro/replica.my.cnf is readable by the tool itself:

scfc@tools-bastion-03:~$ ls -l ~tools.alvaro/replica.my.cnf 
-r-------- 1 tools.alvaro tools.alvaro 52 Apr 25  2016 /data/project/alvaro/replica.my.cnf
scfc@tools-bastion-03:~$

So you can become alvaro and, for example, cat replica.my.cnf.

(BTW, regarding "I need the credentials of my database to install MediaWiki on my server for testing purposes", I'm not sure what that means, but it's probably wrong to try and won't work anyway.)

In T158568#3040987, @scfc wrote:

The file /data/project/alvaro/replica.my.cnf is readable by the tool itself:

scfc@tools-bastion-03:~$ ls -l ~tools.alvaro/replica.my.cnf 
-r-------- 1 tools.alvaro tools.alvaro 52 Apr 25  2016 /data/project/alvaro/replica.my.cnf
scfc@tools-bastion-03:~$

So you can become alvaro and, for example, cat replica.my.cnf.

(BTW, regarding "I need the credentials of my database to install MediaWiki on my server for testing purposes", I'm not sure what that means, but it's probably wrong to try and won't work anyway.)

@scfc No matter, discard as an previous option. But thanks for the info anyway, I'm not an expert on this from the command lines and that's why I did not understand it. Regards.