Flying_Phoenix said:
on a terminal do a "gksudo gedit /etc/modprobe.d/psmouse.modprobe"
That will give you a text editor with the file you modified. Now you only have to delete "options psmouse proto=exps" from the file and save it, then reboot and it should be fixed.
And there on the post you linked it says the good steps on the 11th post
http://ubuntuforums.org/showpost.php?p=8989185&postcount=11
it's more complicated as you have to patch and compile the mouse driver but it will be better.
EDIT: I rather explain it better what you did in the first place.
The command "echo" will just repeat whatever you write after it, so if you write "echo I'm the best" the output will be "I'm the best".
In the first post, what they do is output "options psmouse proto=exp" and redirect it to a file with the operator ">". That means that all the output from the command on the left will be directed to the command/file on the right. Thus with the command:
"echo options psmouse proto=exps > /etc/modprobe.d/psmouse.modprobe"
you create a file called psmouse.modprobe with "options psmouse proto=exps" inside it. It will be same as creating a new document, writing that and saving it with the name psmouse.modprobe" in /etc/modprobe.d/
You can practice the redirections as they are really useful in command line. >, < and | are awesome.
You can test it with:
"echo I'm the best > whatiam.txt" and then open the text file with any editor.
For example, there is a command that shows the kernel messages. It's not used on a daily basis, but it's really useful to find problems with devices and such. The command is "dmesg". The only problem is, that the output is huge so the terminal is unable to show it all.
With "dmesg > dmesg.txt" you would be saving the output of the command to a text file so you can check it later on a text editor.
But there is more, you want to check it on the terminal line by line?
Then execute "dmesg | more"
Command line is the most powerful thing on linux
Regarding the security, root should never ever use the system at all. Ubuntu doesn't even have the root account enabled and it uses sudo as alternative. "super user do" (as in, do a command with another user's privileges)
Taking into account that root is the owner of the whole system, including devices like the HDD it's not a good practive to run always as him.
The best example is the rm command. rm deletes a file/folder without further confirmation. It's commonly used with the -R switch in order to be recursive. If one day you want to remove /home but miss and just write / you are deleting the whole system. Same for special files like configuration files, or programs.
Basically you are playing with fire.
Also, programs should never run with root privileges as they can open unwanted holes in the system. For example, if you run a web server, windows shares, a printer in the network and the software has a hole, if someone gains access he owns the sytem, he can do anything, including kicking you out of your pc. Programs and services are always run with their own user/group combination that is restricted or with a general, limited account that doesn't compromise the whole system if it fails.