Ubuntu 12.04: "you Do Not Have Permissions Necessary To Open The File."

[gl556tr]

__Hello, I have had Ubuntu for a few weeks, but now wanted to check for any possible Rootkits. Getting one's head around the Terminal command line was time-consuming. But with "sudo rkhunter -c --noappend-log --sk --unlock --display-logfile" I had a result, which I was informed was stored in a file called "rkhunter.log" situated in the folder "/var/log".__By changing the View options of the Home Folder, I found this file and clicked on "Open With Text Editor".__Instead of seeing the results of this check for Rootkits, an error message stated that this file could NOT be opened, as I did not have the required permissions.__As I am the sole person using this computer, I would have thought I must therefore have ALL permissions = Administrator (or whatever they're called in the Unix world).__Can anybody please enlighten me and/or point me to an Idiot's Course on Ubuntu & Use of Permissions. Thank you.