At the end of the .bashrc file insert the following code

export PS1="\u> "

Now logout and then log back in again and your prompt should be
username>
The \u indicated that you wanted the username displayed for a full list of commands please visit here

IBM Prompt Sequences

/var/log/

your working directory then issue the command

grep NOT auth.log

You can also add some grep arguments. For a brief rundown on grep grep rundown or use the man grep command

grep science science-paper

That would search the file science-paper for the word science and show the line where the word is located

If you want to ignore case sensitivity, in that if you issue the command

grep ScIeNce science-paper

then the word science would still be returned, then simply include the argument

-i

So the command would be

grep -i ScIeNce science-paper

Other grep arguments include

-v display lines that don’t match
-n precede each matching line with the line number
-c print only the number of matched lines

To issue the grep command with multiple arguments just bunch all the arguments together like this

grep -in science science-paper

that would display each line precede with the line number as we include the -n argument as well

head filename

If you want to view the Last 10 Lines in a file just replace head with tail

tail filename

man ls

This would display a file telling you what the ls command does, it list files, but it will also tell you any arguments that can be issues with the command such as

ls -a

which would display all files and folders in the current directory including hidden files and folders. In Unix/Linux files and folders are hidden if the first character in the name is a full stop

.my-folder

my-folder is a hidden folder and would not show up on the normal ls command

But if you just ran that command then yo will probably find out that it scrolls so add a few arguments to it

history | less

The | or pipe command is found on the backslash key \ so Shift + Backslash gives you the pipe.

/etc/motd

To edit as root, either login as root or on debian based systems (debian and most *buntu systems) simply insert sudo before the command
sudo pico /etc/motd

Substitute pico for you prefered editor if you wish.

Schedule jobs to be executed at noon
at noon

Then the at prompt its displayed
at>

To issue the command to be executed at the specified time just type the command into the at prompt

at>who

then press Ctrl+D to exit the at prompt. Then at noon the command who will be executed

To view a list of pending jobs & job id’s, issue the command
atq

To delete a pending job simply issue the atrm command followed by the job id
atrm 3

WARNING: You must be root to shutdown the system

Shutdown immediately

shutdown -h now

Shutdown in 10 minutes

shutdown -h +10

Reboot immediatly

shutdown -r now

Shutdown at specified time, in this case 20:00 8pm. This can also be used for a restart simply replace -h with -r

shutdown -h 20:00

Shutdown with your own shutdown message

To place your own message on the shutdown warning just add the following line

shutdown -h +5 "Stop work start party"

This would display the message that the computer will shutdown in 5 minutes along with your party message.

“The greeter application appears to be crashing attempting to use a different one”

Go to

System->Admin->login

Under the tab Uncheck the Accessible tab

If no greeter application loads not even the “Emergency” one then take a look here http://liltux.wordpress.com/2007/09/05/how-to-fix-the-error-the-greeter-application-appears-to-be-crashing-in-ubuntu/