Jesus christ the answers here....
cd ~
Replace all instances of linux64 with linux32 if you're using 32 bit Ubuntu.
wget https://www.torproject.org/dist/torbrowser/4.0.3/tor-browser-**linux64**-4.0.3_en-US.tar.xz
wget https://www.torproject.org/dist/torbrowser/4.0.3/tor-browser-**linux64**-4.0.3_en-US.tar.xz.asc
Import Tor's signing key
gpg --keyserver x-hkp://pool.sks-keyservers.net --recv-keys 0x416F061063FEE659
Check it
gpg --fingerprint 0x416F061063FEE659
You should see:
pub 2048R/63FEE659 2003-10-16
Key fingerprint = 8738 A680 B84B 3031 A630 F2DB 416F 0610 63FE E659
uid Erinn Clark <[email protected]>
uid Erinn Clark <[email protected]>
uid Erinn Clark <[email protected]>
sub 2048R/EB399FD7 2003-10-16
Verify the file you downloaded against Tor's signing key (remember to change linux64 to linux32 if necessary)
gpg --verify tor-browser-linux64-4.0.3_en-US.tar.xz.asc
You should see this:
gpg: Signature made Wed 31 Aug 2011 06:37:01 PM EDT using RSA key ID 63FEE659
gpg: Good signature from "Erinn Clark <[email protected]>"
gpg: aka "Erinn Clark <[email protected]>"
gpg: aka "Erinn Clark <[email protected]>"
gpg: WARNING: This key is not certified with a trusted signature!
gpg: There is no indication that the signature belongs to the owner.
Primary key fingerprint: 8738 A680 B84B 3031 A630 F2DB 416F 0610 63FE E659
Unpack Tor Browser:
tar xpvf tor-browser-linux64-4.0.3_en-US.tar.xz
You'll now have 2 files and a folder:
tor-browser-linux64-4.0.3_en-US.tar.xz tor-browser-linux64-4.0.3_en-US.tar.xz.asc tor-browser_en-US/
You can open Tor Browser with the command tor-browser_en-US/./start-tor-browser - but you'll have to keep the terminal open for the time you use Tor Browser.
The alternative is to open the folder tor-browser_en-US in your file explorer and double click start-tor-browser. You should be given the option whether to 'execute' or 'execute in terminal' - choose as appropriate.
Do not fuck around with file permissions as others have suggested.
Hope this helps.