If you get tired of typing your password for sudo, but you don't want (or don't have permissions) to put NOPASSWD in your sudoers file, you can use the following procedure to update the sudo password timestamp and avoid typing your password.

Step 1) Create $HOME/bin/sudo-hack.sh:

#!/bin/bash
while [ true ];
do
    sudo -u root /bin/true > /dev/null 2> /dev/null
    sleep 60
done

Step 2) Do an initial run of sudo to set its password timestamp:

$ sudo -u root /bin/true
Password: *******

Step 3) Start $HOME/bin/sudo-hack.sh in the background:

$ HOME/bin/sudo-hack.sh &

Now you can use sudo without getting a password prompt, regardless of how long it's been since the last time you ran sudo.

Note: there are most certainly security implications related to using this procedure; of course, that's also true of using NOPASSWD in the sudoers file.

The following methods can be used for resetting the root password if the root password is unknown.

If you use GRUB for booting, select the system to be booted, and add 1 to the end of the kernel boot command. If you're not presented with an edit “box” to add boot parameters, try using GRUB's edit command (the letter e). The 1 tells the kernel to boot to single-user mode.

The system now should boot to a root prompt. At this point, simply use the passwd command to change the root password.

Another option is to boot a rescue CD or an installation CD that lets you get to the command line. Once you're at a command prompt, mount the system's root directory if it's not already mounted:

$ mkdir /mnt/system
$ mount /dev/sda1 /mnt/system

Now, do a chroot and reset the password:

$ chroot /mnt/system
$ passwd