Question: I have Xcode installed, but when I type `gcc` in terminal I get "command not found". Maybe I messed up the `$PATH` variable? What is suposed to be the default value?

EDIT:

```
(...):/ imac2$ echo $PATH

/opt/local/bin:/opt/local/sbin:/Applications/SenchaSDKTools-2.0.0-Beta/jsbuilder:/Applications/SenchaSDKTools-2.0.0-Beta/bin:/Applications/SenchaSDKTools-2.0.0-Beta:/usr/bin:/bin:/usr/sbin:/sbin:/usr/local/bin:/usr/X11/bin

```

Answer: 
You need to install the Xcode command-line developer tools. Open Xcode and go to Xcode → Preferences → Downloads, select the Components tab, and click the button next to “Command Line Tools”.

See [Is the installation of Xcode from App Store enough for having the developer tools?](https://apple.stackexchange.com/q/40750/4408).
If you installed the latest Xcode 4.3.2, you'll need to download the optional Command Line Tools component before you can use Terminal to access it. To do this, 

1. click on the **Preferences…** menu
2. a new window will appear, locate and click the **Downloads** icon at the top of that window.
3. In the **Components** view on the left, click on the **Install** button on the right to install the *Command Line Tools*.

After you install it, you should something similar to the following
![enter image description here](https://i.stack.imgur.com/dKj9S.png)