How can I start 'synaptic' and 'sysv-rc-conf' without entering a password all the time? I want to be able to start both of these programs without the needing to enter a password all the time.

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You can only do this as root. If you are going to be doing a lot of work with Synaptic simply open a the terminal and become su. As long as the terminal remains open you can evoke synaptic from the command line without any further re-entering a password.

If you are not used to being root be very careful what you ask of the command line.

Alternately you could evoke synaptic once and leave it open but move it to another work area out of the way. Flip to that work area when you needed synaptic again and it will be there ready to work.

Why don't you want the user to enter a password to use these things? Are you sure that it will only ever be you? Are ou sure there will never be an exploit for these things?

It is possible that what you are attempting to do already has a secure solution.