cp file1 file2 is the command which makes a copy
file1 in the current working directory and
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
to copy it to your
cd to your
Web browsers tend to put it into a
directory, so we will then copy it into your home directory with
cp Downloads/science.txt .
The above command means copy the file
to the current directory (
.), keeping the name
mv file1 file2 moves (or renames)
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
First, change directories to your
(can you remember how?). Then, inside the
mv science.bak backups/.
ls backups to
see if it has worked.
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.
unixstuff directory, type
cp science.txt tempfile.txt,
ls (to check if it has created the file),
rm tempfile.txt and
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.
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 can be used to display the
contents of a file on the screen. Type:
. As you can see, the file is longer than than the size of
the window, so it scrolls past making it unreadable.
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
cat for long files.
head command writes the first ten lines of a
file to the screen.
First clear the screen then type
head -5 science.txt . What difference
-5 do to the head command?
less, you can search though a text file for
a keyword (pattern). For example, to search through
science.txt for the word
less science.txt then, still in
less (i.e. don't press
to quit), type a forward slash
[/] followed by
the word to search, i.e.
As you can see,
less finds and highlights the
n to search for the next occurrence
of the word.
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?
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:
display those lines that do NOT match,
each maching line with the line number,
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
move or rename |
||remove a file|
remove a |
display a file called |
display a file called |
display the first few lines of a file called
display the last few lines of a file called
search a file called |
count number of lines/words/characters in a file called