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I have downloaded the Eset Nod32 Antivirus from its website, and I got a eset_nod32av_64bit_en.linux file. I have right-clicked on it, Properties - Permissions, and checked the Allow executing file as program option. Then I was able to run the program. The Installer starts and it asks for my root password. I enter it correctly, but then I get the following error message: su: Authentication failure. What can I do with this to install the Nod32?

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possible duplicate of su command + authentication failure – Eliah Kagan Aug 8 '14 at 23:29

Ubuntu DOES use sudo instead of su but this doesn't really solve the problem long term. In order to solve this problem for good you need to change the su password. Unfortunately to change the su password in Ubuntu you can't just use the passwd command. You need to use a combination of sudo with passwd like this:

user@user-ubuntu1:~$ sudo passwd
[sudo] password for user: # enter your sudo password here
Enter new UNIX password: # enter the password you want for your su password here
Retype new UNIX password: # reenter your new su password
passwd: password updated successfully

And there you have it - no more errors.

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Ubuntu uses sudo


sudo ./eset_nod32av_64bit_en.linux

See: for details.

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