/root/tarsnap.key: file in which to store the keys used to create and access archives.
firstname.lastname@example.org: the email address you used to sign up with Tarsnap.
mybox: the desired machine name.
Enter your Tarsnap account password when prompted.
6. Keep your key file safe
Store your /root/tarsnap.key somewhere safe.
If you lose tarsnap.key, you will not be able to access your archived data.
There are many ways to keep it safe:
Copy it to a different system.
Put it on a USB disk.
Give it to a friend.
Print it out (it is printable text).
Store it in a bank vault.
Pick at least one and do it!
At the present time, pre-built binaries are not available for Tarsnap — it must be compiled from the source code. Some operating systems include Tarsnap packages (e.g., the FreeBSD Tarsnap port, NetBSD Tarsnap port), which automate the compiling and installation process.
If you wish to compile manually,
Download the latest source tarball and SHA256 hash file (below).
If DIR is specified, it installs to that directory.
If DIR is left blank, it attempts to use pkg-config and bash-completion >= 2.0 to determine where to put the bash completion scripts. If your system does not match those requirements, please specify DIR explicitly.