You can run the deinstall command from an Oracle home directory after installation.

deinstall stops Oracle software, and removes Oracle software and configuration files on the operating system for a specific Oracle home.

Please note deinstall command also delete/remove your databases associated with respective oracle home from where invoke deinstall command. 

*** Please DO NOT try until comfortable.

[oracle@rac1 ~]$  /u01/app/oracle/product/19.0.0/db_1/deinstall/deinstall
Checking for required files and bootstrapping ...
Please wait ...
Location of logs /u01/app/oraInventory/logs/

############ ORACLE DECONFIG TOOL START ############


######################### DECONFIG CHECK OPERATION START #########################
## [START] Install check configuration ##


Checking for existence of the Oracle home location /u01/app/oracle/product/19.0.0/db_1
Oracle Home type selected for deinstall is: Oracle Single Instance Database
Oracle Base selected for deinstall is: /u01/app/oracle
Checking for existence of central inventory location /u01/app/oraInventory

## [END] Install check configuration ##


Network Configuration check config START

Network de-configuration trace file location: /u01/app/oraInventory/logs/netdc_check2020-01-26_02-51-37PM.log

Network Configuration check config END

Database Check Configuration START

Database de-configuration trace file location: /u01/app/oraInventory/logs/databasedc_check2020-01-26_02-51-37PM.log

Use comma as separator when specifying list of values as input

Specify the list of database names that are configured in this Oracle home []:
Database Check Configuration END

######################### DECONFIG CHECK OPERATION END #########################


####################### DECONFIG CHECK OPERATION SUMMARY #######################
Oracle Home selected for deinstall is: /u01/app/oracle/product/19.0.0/db_1
Inventory Location where the Oracle home registered is: /u01/app/oraInventory
Do you want to continue (y - yes, n - no)? [n]: y
A log of this session will be written to: '/u01/app/oraInventory/logs/deinstall_deconfig2020-01-26_02-51-34-PM.out'
Any error messages from this session will be written to: '/u01/app/oraInventory/logs/deinstall_deconfig2020-01-26_02-51-34-PM.err'

######################## DECONFIG CLEAN OPERATION START ########################
Database de-configuration trace file location: /u01/app/oraInventory/logs/databasedc_clean2020-01-26_02-51-37PM.log

Network Configuration clean config START

Network de-configuration trace file location: /u01/app/oraInventory/logs/netdc_clean2020-01-26_02-51-37PM.log

De-configuring backup files...
Backup files de-configured successfully.

The network configuration has been cleaned up successfully.

Network Configuration clean config END


######################### DECONFIG CLEAN OPERATION END #########################


####################### DECONFIG CLEAN OPERATION SUMMARY #######################
#######################################################################


############# ORACLE DECONFIG TOOL END #############

Using properties file /tmp/deinstall2020-01-26_02-51-17PM/response/deinstall_2020-01-26_02-51-34-PM.rsp
Location of logs /u01/app/oraInventory/logs/

############ ORACLE DEINSTALL TOOL START ############





####################### DEINSTALL CHECK OPERATION SUMMARY #######################
A log of this session will be written to: '/u01/app/oraInventory/logs/deinstall_deconfig2020-01-26_02-51-34-PM.out'
Any error messages from this session will be written to: '/u01/app/oraInventory/logs/deinstall_deconfig2020-01-26_02-51-34-PM.err'

######################## DEINSTALL CLEAN OPERATION START ########################
## [START] Preparing for Deinstall ##
Setting LOCAL_NODE to rac1
Setting CRS_HOME to false
Setting oracle.installer.invPtrLoc to /tmp/deinstall2020-01-26_02-51-17PM/oraInst.loc
Setting oracle.installer.local to false

## [END] Preparing for Deinstall ##

Setting the force flag to false
Setting the force flag to cleanup the Oracle Base
Oracle Universal Installer clean START

Detach Oracle home '/u01/app/oracle/product/19.0.0/db_1' from the central inventory on the local node : Done

Delete directory '/u01/app/oracle/product/19.0.0/db_1' on the local node : Done

The Oracle Base directory '/u01/app/oracle' will not be removed on local node. The directory is in use by Oracle Home '/u01/app/oracle/middleware'.

Oracle Universal Installer cleanup was successful.

Oracle Universal Installer clean END


## [START] Oracle install clean ##


## [END] Oracle install clean ##


######################### DEINSTALL CLEAN OPERATION END #########################


####################### DEINSTALL CLEAN OPERATION SUMMARY #######################
Successfully detached Oracle home '/u01/app/oracle/product/19.0.0/db_1' from the central inventory on the local node.
Successfully deleted directory '/u01/app/oracle/product/19.0.0/db_1' on the local node.
Oracle Universal Installer cleanup was successful.

Review the permissions and contents of '/u01/app/oracle' on nodes(s) 'rac1'.
If there are no Oracle home(s) associated with '/u01/app/oracle', manually delete '/u01/app/oracle' and its contents.
Oracle deinstall tool successfully cleaned up temporary directories.
#######################################################################


############# ORACLE DEINSTALL TOOL END #############

[oracle@rac1 ~]$

[oracle@rac1 ~]$ ls -ld /u01/app/oracle/product/19.0.0/db_1
ls: cannot access /u01/app/oracle/product/19.0.0/db_1: No such file or directory
[oracle@rac1 ~]$
[oracle@rac1 ~]$ cd /u01/app/oraInventory/ContentsXML
[oracle@rac1 ContentsXML]$ cat inventory.xml | grep -i "/u01/app/oracle/product/19.0.0/db_1"
[oracle@rac1 ContentsXML]$