This assume you are able to log into your MariaDB or mySQL server .The user table in the mysql database your mysql users. You can display the users in the mysql user table like this.

mysql -u root --password=itsasecret "use mysql; select * from user \G"

Or, if you have configured passwordless authentication the -e command line option can be used.

mysql -e "use mysql; select * from user \G"

Or like this.

mysql -e "select * from mysql.user \G"

Something like this should be returned for each user.

                  Host: %
                  User: john.doe
              Password: *B87A204DF7CFB2D1ABC123456JFH0DC081CD35EF2
           Select_priv: Y
           Insert_priv: Y
           Update_priv: Y
           Delete_priv: Y
           Create_priv: Y
             Drop_priv: Y
           Reload_priv: N
         Shutdown_priv: N
          Process_priv: N
             File_priv: N
            Grant_priv: Y
       References_priv: N
            Index_priv: N
            Alter_priv: Y
          Show_db_priv: N
            Super_priv: N
 Create_tmp_table_priv: N
      Lock_tables_priv: N
          Execute_priv: N
       Repl_slave_priv: N
      Repl_client_priv: N
      Create_view_priv: N
        Show_view_priv: N
   Create_routine_priv: N
    Alter_routine_priv: N
      Create_user_priv: N
            Event_priv: N
          Trigger_priv: N
Create_tablespace_priv: N
              ssl_type:
            ssl_cipher:
           x509_issuer:
          x509_subject:
         max_questions: 0
           max_updates: 0
       max_connections: 0
  max_user_connections: 0
                plugin:
 authentication_string: