How to clear Mac OSX icon cache

I recently downloaded an application named 'keka". It was used to unarchive .rar files. The application had it's own file logo (which looks like this):

I deleted the app, and the files that were included with the app. I restarted my Mac... And the logo was the same. So I downloaded another .rar file, and the logo was the same. I tried to follow the following procedure:

To fix this, we need to Clear Mac OS X's icon cache.Here is how:

1. To get started, close all open applications and then launch Terminal from Macintosh HD > Applications > Utilities. Copy and paste the following command at the Terminal prompt and press Return to execute it:

2. sudo find /private/var/folders/ -name 'com.apple.dock.iconcache' -delete 
   sudo find /private/var/folders/ -name 'com.apple.iconservices' -delete sudo rm -r /Library/Caches/com.apple.iconservices.store

3. restart,job done.

^from Apple.Stackexchange.com (macos - Safari download bar rar file icon show as VLC icon,which associate to The Unarchiver should shows its icon - Ask…)

When I did the first and second sudo commands, the return was the following:
find: (file name here): Operation not permittedIf anyone has any solutions? Thanks in advance
- V. Patel