How can I sort file names by version numbers?

Question

In the directory \"data\" are these files:

command-1.9a-setup
command-2.0a-setup
command-2.0c-setup
command-2.0-setup

Answer 1

$ cat files
command-1.9a-setup
command-2.0c-setup
command-10.1-setup
command-2.0a-setup
command-2.0-setup

$ cat files | sort -t- -k2,2 -n
command-1.9a-setup
command-2.0-setup
command-2.0a-setup
command-2.0c-setup
command-10.1-setup

$ tac files | sort -t- -k2,2 -n
command-1.9a-setup
command-2.0-setup
command-2.0a-setup
command-2.0c-setup
command-10.1-setup