Cleanup a failed Oracle XE installation on Linux Mint

On this Blog I described on how to install Oracle XE on a current Linux Mint version (19.3. Tricia when writing the Blog). After the conversion of the Oracle provided rpm to a deb installation file with the tool alien, you can install the Oracle XE software with a simple command

root@clemens-TravelMate:/opt/distr# dpkg -i oracle-database-xe-18c_1.0-2_amd64.deb

If the installation fails or the XE database cannot be created with the configuration script later on, then you have to be able to remove the software again and do the cleanup on the system. However, this is often not possible that easily with “dpkg -r oracle-database-xe-18c”, because the pre-removal script or post-removal script may fail leaving the deb-repository untouched.

To remove the software you may follow the steps below:

REMARK: It is assumed here that there is no other Oracle installation in the oraInventory.

1.) Make sure the Listener and the XE database is stopped

If there is no other way then you may kill the listener and pmon process with e.g.

root@clemens-TravelMate:~# kill -9 $(ps -ef | grep tnslsnr | grep -v grep | tr -s " " | cut -d " " -f2)
root@clemens-TravelMate:~# kill -9 $(ps -ef | grep pmon | grep -v grep | tr -s " " | cut -d " " -f2)

2.) Skip the pre-removal skript by just putting an “exit 0” at the beginning of it

root@clemens-TravelMate:~# vi /var/lib/dpkg/info/oracle-database-xe-18c.prerm
...
root@clemens-TravelMate:~# head -2 /var/lib/dpkg/info/oracle-database-xe-18c.prerm
#!/bin/bash
exit 0

3.) Remove the Oracle installation

root@clemens-TravelMate:~# rm /etc/oratab /etc/oraInst.loc
root@clemens-TravelMate:~# rm -rf /opt/oracle/*

Remark: Removing the oraInst.loc ensures that the postrm-script /var/lib/dpkg/info/oracle-database-xe-18c.postrm is skipped.

4.) Remove the deb-package

root@clemens-TravelMate:~# dpkg --purge --force-all oracle-database-xe-18c

5.) Cleanup some other files

root@clemens-TravelMate:~# rm -rf /var/tmp/.oracle
root@clemens-TravelMate:~# rm -rf /opt/ORCLfmap/

Done.