The document provides information about the vi editor, including: 1. Vi is a text editor that is included with Linux and Unix operating systems. It preceded vim and was originally created by Bill Joy in 1976. 2. Vi has three modes - command mode, input mode, and Ex mode. Command mode is accessed with Esc and is used to enter commands, input mode is accessed with "i" and allows text insertion/editing, and Ex mode appears on the last line. 3. Input and output redirection and piping allow vi commands to take input from or send output to files rather than the keyboard/screen. Redirectors like > and < and piping with | connect the output of one command

1. VI editor

2. AGENDA
» WHAT IS VI EDITOR?
» HISTORY OF VI.
» CHARACTERISTIC OF VI.
» STARTING VI
» MODE IN VI EDITOR.
» COMMON VI COMMAND
» HOW TO EXIT FROM VI

3. HELLO!

4. 1.
WHAT IS VI

5. » The visual editor on the Linux.
» The vi editor comes with every version of Linux or Unix.
» Using vi is similar to using other editors in that you can see your file on the
screen ..
» The vi editor is the most popular editor in linux. The current version is
» really "vim", but to invoke it simply type "vi".
» Before vi the primary editor used on Unix was the line editor
⋄ - User was able to see/edit only one line of the text at a time
» The vi editor is not a text formatter (like MS Word, Word Perfect, etc.)
⋄ - you cannot set margins
⋄ - center heading
⋄ - Etc…”
» Although other stories exist, the true one tells that vi was originally written
» by Bill Joy in 1976.
» Who is Bill Joy you ask?
- He co-founded Sun Microsystems in 1982
and served as chief scientist until 2003.

6. The vi editor is:
» - A very powerful
» - It is hard to learn, specially for windows
users
» - Move from point to point in the file, and
make changes.
» - Available on all UNIX systems

7. Vi modes

8. » - Command mode
⋄ - Accessed by typing Esc
⋄ - In this mode all the keys pressed by the user are interpret to the editor command.
» - Input mode
⋄ - Accessed by typing “i”
⋄ - This mode permits insertion of new text, editing of existing text or replacement of existing text.
» Ex mode( Last Line Mode)
⋄ -The bottom line of the vi screen is called ex mode.
⋄ - When you start vi by default it is in command mode
» -You exit the input mode by pressing the Esc key to get back to the command mode.
There are three modes in vi

9. I/P & O/P
REDIRECTION

10. Most Linux commands read input, such as a file or another
attribute for the command, and write output. By default,
input is being given with the keyboard, and output is
displayed on your screen.
Your keyboard is your standard
input (stdin) device, and the screen or a particular terminal
window is the standard output (stdout) device.
However, since Linux is a flexible system, these
default settings don't necessarily have to be applied. The
standard output, for example, on a heavily monitored
server in a large environment may be a printer.

11. Output redirection with > and Input
redirection with <
The> operator tells unix, “Don’t display this output on screen instead , put it
somewhere else”. Likewise the < operator says “ the input for this command is not
coming from the keyboard this time look for somewhere else”.
The somewhere else can be a file or a printer for output redirection and a
file or a keyboard for input redirection.

12. Example
$cat file1 > file2
$cat test1
some words
$ cat test2
some other words
$ cat test1 test2 > test3
$cat test3
some words some other words

13. Example
$cat file1 < file2
$cat < test3
some words
some other words

14. Example
Sometime we may use both the redirection operators at once as
shown below
$ cat < currentfile > newfile
input is taken fron currentfile and output is stored in
newfile
$ cat < currentfile > newfile
is also same

15. Example
Another redirection operator is
>>
Example
$who >> logfile
it is similar to > except if the target
file already existing the new output is append to its end
This command append current users who have
logged in to the end of logfile

16. PIPING
COMMAND 1
COMMAND
2
COMMAND
3

17. Quite often a single unix command is not suffice to solve a
problem or do a task. That’s the time we can try joining
command together. The chief tools for this are redirection and
piping.
The unix piping facility lets us to connect commands to other commands. It
can be really useful to redirect the output of one program so that it became
the input of another program. Incidentally such commands are known as
filters.
Thus a filter is a program which can receive a flow of data from standard
input, process it and send the results to the standard output.

18.  cat concatenates and display file
More display a file one screen full at atime
Grep searches file for pattern
Sort sorts and merges file
Wc count lines, words and characters
Unique reports repeated lines in file

19. EXAPMLE
1. $LS | WC –L
Output of ls becomes the input of wc
2. $ ls | wwc –l > countfile