====== Extract ======
To extract from a USB drive the best syntax is
<code>
gunzip -c /media/usb_drive1/file.tar.gz | tar -xvf -
</code>

The -c option extract to standard output which is the console. 
<code>
-c --stdout --to-stdout
Write  output on standard output; keep original files unchanged
</code>
This is piped to tar. So if you keep the current directory where you want the extracted files to be, you can directly unzip from the USB drive