Hi Paul and Jaya,
While I can't speak specifically to a Unix installation, in the Windows environment I do not recommend using the command-line to install the license, but rather the TaxFactory GUI client. So, you aren't directly logged onto the server console at all, but do this from your workstation. Launch the client and connect and logon as the TF10 user there. I cover this in my blog at BSI TaxFactory 10 Installation for SQL Server - Part 3, and while the blog is oriented toward SQL Server installations, the license key installation portion should be pretty much the same.
Cheers,
Matt