sudo htpasswd /etc/subversion/passwd username
New password: *******
Re-type new password: *******
Adding password for user username
OS: Ubuntu 12.04 LTS
English uppercase characters (A through Z)
English lowercase characters (a through z)
Base 10 digits (0 through 9)
Non-alphabetic characters (for example, !, $, #, %)
Enabled on domain controllers.
Disabled on stand-alone servers.
Note: By default, member computers follow the configuration of their domain controllers.