The above command means copy the file science.txt to the current directory, keeping the name the same.

Moving files
mv (move)
mv file1 file2 moves (or renames) file1 to file2 
It can also be used to rename a file, by moving the file to the same directory, but giving it a different name. 
We are now going to move the file science.bak to your backup directory. 
First, change directories to your unixstuff directory (can you remember how?). Then, inside the unixstuff directory, type
% mv science.bak backups/.
Type ls and ls backups to see if it has worked.

Removing files and directories
rm (remove), rmdir (remove directory)
To delete (remove) a file, use the rm command. As an example, we are going to create a copy of the science.txt file then delete it. 
Inside your unixstuff directory, type
% cp science.txt tempfile.txt
% ls
% rm tempfile.txt
% ls
You can use the rmdir command to remove a directory (make sure it is empty first). Try to remove the backups directory. You will not be able to since UNIX will not let you remove a non-empty directory.

clear (clear screen)
Before you start the next section, you may like to clear the terminal window of the previous commands so the output of the following commands can be clearly understood. 
At the prompt, type 
% clear 
This will clear all text and leave you with the % prompt at the top of the window. 
cat (concatenate)
The command cat can be used to display the contents of a file on the screen. Type: 
% cat science.txt 
less
The command less writes the contents of a file onto the screen a page at a time. Type 
% less science.txt 
Press the [space-bar] if you want to see another page, and type [q] if you want to quit reading. As you can see, less is used in preference to cat for long files. 
head
The head command writes the first ten lines of a file to the screen. 
First clear the screen then type 
% head science.txt 
Then type 
% head -5 science.txt 

tail
The tail command writes the last ten lines of a file to the screen. 
Clear the screen and type 
% tail science.txt
Searching the contents of a file 
Simple searching using less
Using less, you can search though a text file for a keyword (pattern). For example, to search through science.txt for the word 'science', type 
% less science.txt 
then, still in less, type a forward slash [/] followed by the word to search
/science
As you can see, less finds and highlights the keyword. Type [n] to search for the next occurrence of the word.

grep 
grep is one of many standard UNIX utilities. It searches files for specified words or patterns. First clear the screen, then type 
% grep science science.txt 
As you can see, grep has printed out each line containing the word science. 
The grep command is case sensitive; it distinguishes between Science and science. 
To ignore upper/lower case distinctions, use the -i option, i.e. type 
% grep -i science science.txt 
To search for a phrase or pattern, you must enclose it in single quotes (the apostrophe symbol). For example to search for spinning top, type 
% grep -i 'spinning top' science.txt
Some of the other options of grep are: 
-v display those lines that do NOT match 
-n precede each matching line with the line number
-c print only the total count of matched lines 
wc (word count)
A handy little utility is the wc command, short for word count. To do a word count on science.txt, type 
% wc -w science.txt 
To find out how many lines the file has, type 
% wc -l science.txt