Unable to LOAD_FILE in Maria DB - mariadb

Question

I am using Maria DB on Ubuntu 1804 :
Welcome to the MariaDB monitor. Commands end with ; or \g.
Your MariaDB connection id is 37
Server version: 10.1.44-MariaDB-0ubuntu0.18.04.1 Ubuntu 18.04
I want to do something relatively easy and I have wasted 2 hours on it. I want to load a file as a string. There are several questions (many of them really old) on this site but none of them lead me to a solution and I have tested everything til reaching total frustration.
Granting privileges :
MariaDB [(none)]> GRANT FILE ON *.* TO matias#localhost;;
Query OK, 0 rows affected (0.00 sec)
ERROR: No query specified
MariaDB [(none)]> flush privileges;
Query OK, 0 rows affected (0.00 sec)
MariaDB [(none)]> SHOW GRANTS FOR matias#localhost
-> ;
+------------------------------------------------------------------------------------------------------------------------+
| Grants for matias#localhost |
+------------------------------------------------------------------------------------------------------------------------+
| GRANT ALL PRIVILEGES ON *.* TO 'matias'#'localhost' IDENTIFIED BY PASSWORD '*???' |
+------------------------------------------------------------------------------------------------------------------------+
1 row in set (0.00 sec)
No secure_file_priv :
MariaDB [(none)]> SHOW VARIABLES LIKE 'secure_file_priv';
+------------------+-------+
| Variable_name | Value |
+------------------+-------+
| secure_file_priv | |
+------------------+-------+
1 row in set (0.00 sec)
Right permissions on the file :
[~]#Ubuntu1804 #> ls -lh test.txt
-rw-rw-r-- 1 matias matias 6 Feb 29 23:44 test.txt
And still cant get the file :
MariaDB [(none)]> SELECT USER();
+------------------+
| USER() |
+------------------+
| matias#localhost |
+------------------+
1 row in set (0.00 sec)
MariaDB [(none)]> SELECT LOAD_FILE('/home/matias/test.txt');
+------------------------------------+
| LOAD_FILE('/home/matias/test.txt') |
+------------------------------------+
| NULL |
+------------------------------------+
1 row in set (0.00 sec)
Can someone point me on the right direction to solve this?

Answer 1

Well, I tried EVERYTHING under the sun and it never worked.
So I tried with Ubuntu 19.10 instead of 18.04 and it works like charm,
so unless someone has some magic card on his sleeve this is the only workaround I could come up with.
All in all, it works in Ubuntu 16.04 and 19.10.