Quick easy way to determine if your *nix system is vulnerable to Shellshock

Run this command from your terminal:

x='() { :;}; echo VULNERABLE' bash -c :

Systems that are vulnerable will return:

$ x='() { :;}; echo VULNERABLE' bash -c :
VULNERABLE

Systems that have been patched will return:

$ x='() { :;}; echo VULNERABLE' bash -c :
bash: warning: x: ignoring function definition attempt
bash: error importing function definition for `x'

For an in depth analysis and explanation go here: http://security.stackexchange.com/questions/68168/is-there-a-short-command-to-test-if-my-server-is-secure-against-the-shellshock-b

This guy does a much better job than I could ever hope to.