.. code-block:: console
- % wget ftp://ftp.gnu.org/gnu/gcc/gcc-4.8.2/gcc-4.8.2.tar.bz2
+ % wget https://ftp.gnu.org/gnu/gcc/gcc-4.8.2/gcc-4.8.2.tar.bz2
+ % wget https://ftp.gnu.org/gnu/gcc/gcc-4.8.2/gcc-4.8.2.tar.bz2.sig
+ % wget https://ftp.gnu.org/gnu/gnu-keyring.gpg
+ % signature_invalid=`gpg --verify --no-default-keyring --keyring ./gnu-keyring.gpg gcc-4.8.2.tar.bz2.sig`
+ % if [ $signature_invalid ]; then echo "Invalid signature" ; exit 1 ; fi
% tar -xvjf gcc-4.8.2.tar.bz2
% cd gcc-4.8.2
% ./contrib/download_prerequisites