[FATAL] [INS-32042] The Installer has detected that the user (oracle) is not member of the central inventory group

Silent installation of Oracle client 19c gets the following fatal error:

[FATAL] [INS-32042] The Installer has detected that the user (oracle) is not member of the central inventory group:
   ACTION: Make sure that the user (oracle) is member of the central inventory group ().
INFO:  [Nov 26, 2023 12:08:20 PM] Advice is ABORT

CAUSE

Check oraInst.loc file, and found inst_group is empty for some reason.

$ cat /etc/oraInst.loc
inventory_loc=/u01/app/oraInventory
inst_group=

SOLUTION

Gives inst_group variable in /etc/oraInventory the right value.

$ cat /etc/oraInst.loc
inventory_loc=/u01/app/oraInventory
inst_group=oinstall