Loughborough University
Leicestershire, UK
LE11 3TU
+44 (0)1509 222222
Loughborough University

IT Services : High Performance Computing

Tutorial Two

Copying Files

cp (copy)

cp file1 file2 is the command which makes a copy of file1 in the current working directory and calls it file2

What we are going to do now, is to take a file stored in an open access area of the file system, and use the cp command to copy it to your unixstuff directory.

First, cd to your unixstuff directory, i.e. cd ~/unixstuff

Download science.txt

Web browsers tend to put it into a Downloads directory, so we will then copy it into your home directory with

cp Downloads/science.txt .

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

Exercise 2a

Create a backup of your science.txt file by copying it to a file called science.bak

Moving files, mv (move)

mv file1 file2 moves (or renames) file1 to file2

To move a file from one place to another, use the mv command. This has the effect of moving rather than copying the file, so you end up with only one file rather than two.

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 (to check if it has created the file), rm tempfile.txt and ls (to check if it has deleted the file)

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 Linux will not let you remove a non-empty directory.

Exercise 2b

Create a directory called tempstuff using mkdir, then remove it using the rmdir command.

Displaying the contents of a file on the screen

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 . As you can see, the file is longer than than the size of the window, so it scrolls past making it unreadable.


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, type qif you want to quit reading. As you can see, less is used in preference to cat for long files.


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 . What difference did the -5 do to the head command?


The tail command writes the last ten lines of a file to the screen.

Clear the screen and type tail science.txt. How can you view the last 15 lines of the file?

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 (i.e. don't press q to quit), type a forward slash [/] followed by the word to search, i.e. /science

As you can see, less finds and highlights the keyword. Type n to search for the next occurrence of the word.

grep (don't ask why it is called 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 containg the word science. Or has it?

Try typing grep Science science.txt . 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 to display those lines that do NOT match, -n precede each maching line with the line number, -c print only the total count of matched lines

Try some of them and see the different results. Don't forget, you can use more than one option at a time, for example, the number of lines without the words science or Science is grep -ivc science science.txt

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


Command Description
cp file1 file2 copy file1 and call it file2
mv file1 file2 move or rename file1 to file2
rm file remove a file
rmdir directory remove a directory
cat file display a file called file
less file display a file called filea page at a time
head file display the first few lines of a file called file
tail file display the last few lines of a file called file
grep 'keyword' file search a file called file for keywords defined in 'keyword'
wc file count number of lines/words/characters in a file called file


Original version by M.Stonebank@surrey.ac.uk, 9th October 2000. Modified by a.turner@lboro.ac.uk, 2015.