Shellshock Vulnerability on Bash Shell

This is how you test your bash shell whether its vulnerable or not for 'shellsock' bug.
Run this on your linux shell (you don't need super user account for this):
 $ env x='() { :;}; echo vulnerable' bash -c "echo this is a test" 
if the result like this:
   vulnerable
   this is a test
then, you need to upgrade your bash version.

Just run (as superuser or sudo)
 # apt-get update
 # apt-get upgrade

It will show bash upgrade like this:
 Get:1 http://security.debian.org/ wheezy/updates/main bash amd64 4.2+dfsg-0.1+deb7u3 [1,501 kB]

After I upgrade my bash, the result becames like this:
   this is a test

I use bash version : GNU bash, version 4.2.37(1)-release (x86_64-pc-linux-gnu)

Reference: http://www.debiantutorials.com/how-to-detect-if-your-server-is-vulnerable-to-the-shellshock-bug-and-fix-it/