Whenever I go to use my computer I always get the message "Your computer is running in low graphics mode".
People have directed me to the terminal to enter a command but I don't know what my credentials are.
Open a terminal, enter the command :
sudo <command>
You will be asked for a password, it is the same as your log in password. You will not see anything in the terminal as you type your password. That is normal behavior, just enter your password and hit enter.
ls /home
or use the command id
In Linux (and Unix in general), there is a SuperUser named Root. The SuperUser can do anything and everything, and thus doing daily work as the SuperUser can be dangerous. You could type a command incorrectly and destroy the system. Ideally, you run as a user that has only the privileges needed for the task at hand. In some cases, this is necessarily Root, but most of the time it is a regular user.
By default, the root account password is locked in Ubuntu.
There are also administrator users and normal users
The first account you set up is an administrator user, Subsequent users are not if you need to give another user administrator privileges run the the following command in a terminal
sudo adduser <username> sudo
where you replace username with the name of the user (without the <>).
The root user can run any command without question, which is part of the reason the account is locked by default. Administrators can also run any command but need to ask for special privileges to run restricted commands, normal users can not run restricted commands at all.
As an administrator you can run GUI programs such as nautilus (default file manager) with super user powers by pressing ALT+F2 and typing gksu nautilus
for other programs replace nautilus with the name of the program you want.
For command line programs the syntax is slightly different. To run a command as a super user type
sudo command
replace command with the command you want for example fdisk -l
does nothing because it's a restricted command but sudo fdisk -l
lists all the drives your computer can see.
For both sudo and gksu you will be asked to enter your password.
To find out what credentials you have enter whoami
to get your user name; if it does not say root you are not root. Next enter id
this lists what groups you belong to if sudo is listed you are an administrator, otherwise you are a normal user
There is more information here