How to open a terminal window before the login?

[auie]

Dear All,

I don't know the password of the only account of my iBook G4 that has OS 10.5.8.
There are several methods to bypass this problem.
One of them is to change
(All) All in passwd: all in the single user mode
as it's described here:

Mac OS X Tip - No Password, No Root, No CD? No Problem.

Say you’ve lost your account password, you don’t have a system CD on hand, and you didn’t enable root. Say you have no other way to log into that machine. Say you need access to the files on that machine right now. Say you’re in deep you-know-what, bucko. Fortunately, there’s a five minute fix — […]

www.macobserver.com

I think that I did the 5 first steps of the method and that there is only the 6th step to achieve.
I wrote 'I think', because I'm not sure though the changes (i.e. (All) All in passwd: all) that I made can be seen after I reboot.
I don't think that I used vi.
I only wrote

mount -uw /
sudo visudo

which is advised here:

Pro Terminal Commands: How and Why To Edit Sudoers on macOS - Apple Gazette

Within your macOS system, there’s a file called “sudoers” which controls the deepest levels of your permissions system. This file says which users can run sudo, and what they can do when they run it. Basically, it decides who is in charge. We can edit sudoers on macOS to administer a multi-user...

www.applegazette.com

Please how do you open a terminal before the login to do the 6th step?

 

[Dronecatcher]

Use this guide instead:

How to reset your Mac OS X password without an installer disc | MacYourself

Let's say you totally forgot the password to log on to your Mac. Or maybe you purchased a used Mac from someone else and they've got it locked down. There are numerous ways to reset a password with no OS X discs...

www.macyourself.com

 

[auie]

Thank you very much Dronecatcher, but after I wrote

launchctl load /System/Library/LaunchDaemons/com.apple.DirectoryServices.plist

I get

launch_msg(): Socket is not connected

 

[Dronecatcher]

Thank you very much Dronecatcher, but after I wrote

launchctl load /System/Library/LaunchDaemons/com.apple.DirectoryServices.plist

I get

launch_msg(): Socket is not connected

This may or may not help:

leopard forgot password+launch_msg socket is not connected

I was working on increasing the speed of an ancient (6 years old) iMac running Leopard when I accidentally set the password incorrectly. I then turned to the internet to look for an answer and foun...

apple.stackexchange.com

 

[auie]

Thank you Dronecatcher.
I used 'Tricking your Mac into creating a new user account' from your first link.