When You use ‘sudo’ command it will ask for password in First time and will remember password for 15 minutes. It is a security hole for sensitive systems.
You can change sudo Password Remembering Time in Ubuntu .
Open a terminal and type
$ sudo visudo
In Ubuntu, visudo uses nano text editor, and what it does is edit the / etc / sudoers.tmp
Check for the line as shown below
Defaults env_reset
Change it to
Defaults env_reset , timestamp_timeout = X
Where X is the time that we remember the sudo password, if we put 0 (zero) that we always get the request.
Finally to save the changes, press Ctrl + X and said yes.
If your Ubuntu machine is nor working properly after a partial upgrade and have a have broken the system dependencies tree, You can recover it by using a simple command that reinstalls all the installed packages and reconfigures them automatically.This will take a long time to complete.
$sudo dpkg-reconfigure -phigh -a
You can try the following command first
$ sudo apt-get install -f

