Note there is no easy way to change usernames, see ticket:738.

Add a new Trac user

First sudo to root and then to the tradc user:

sudo -i
su-trac

Export the username you want to add:

export NEWTRACUSER=nickname

To add a user:

trac-admin /web/tech.transitionnetwork.org/trac permission add $NEWTRACUSER admin

To set their password:

htpasswd /web/tech.transitionnetwork.org/.htpasswd $NEWTRACUSER 

You then need to login as the new user to set their email address for email notifications to work via the ​preferences page.

Then go to the ​admin permissions page and use the Grant Permission form to grant users TRAC_ADMIN permissions.

Change a Trac users password

First sudo to root and then to the tradc user:

sudo -i
su-trac

Then change their password,

htpasswd /web/tech.transitionnetwork.org/.htpasswd username