Ubuntu software installation via terminal

[Adayof]

I bought a laptop in asia while travelling and to save money it had linux rather than windows installed, and I have been learning as I move around. Unfortunately I don't have access to the root user because the people in the shop I bought it set a password to the root without telling me and before I learnt about the root etc I was already far away.

Anyway, I've been trying to install Avast! for linux, I have GNU bash, version 3.2.33, and I downloaded the Ubuntu .deb file.

On the avast website it said I should go into the terminal and use the dpkg command but when I tried that it said command not found. I tried install and it asked me for file destination and file source. I don't really know what the specific names of the folders are, its currently stored in my downloads.

Any help regarding the wording and syntax I should use to install the software would be much appreciated.

Thankss!

[Rubberman]

Open a command-line window and try the command sudo su - - if it asks for a password, enter your user password. If that works, you are now in the root user account and can reset the password with the passwd command.

[Rubberman]

In any case, by default on Ubuntu, the root account is disabled. Root privileges are given to the default user account (yours), so you can do admin activities by prefacing such commands with "sudo". Many admin commands are in directories such as /sbin and /usr/sbin which are not in your path by default, so you can change your .bash_profile to add them to the PATH environment, giving you easier access to them. This would probably include commands such as apt-get install pkg-name

[devils casper]

You can gain root privileges through sudo command. sudo and user created during Ubuntu installation share same password. Check this sticky for more details.

You can use Synaptic Package Manager to install packages in Ubuntu. Check more details here.

Here is a link of Short Security Guide.