Ex.No:1 UNIX COMMANDS
Introduction:
The
UNIX operating system developed at Bell laboratories are among the notable
success in the field of operating system. UNIX system provides a friendly
environment for program development and text processing. They make it easy to
combine programs with one another. This encourages a modular total oriented
building block approach to program design.
BASIC UNIX COMMANDS
1. date command:
The date command tells us the
current date and time
Format:
$date
2. who
command:
This
command gives us the details of who have logged into the Unix System.
Format:
$who
$who am i
which
tells us to when we had logged in and the system name for connection being used
3. man
command:
This command
prints manual page
Format:
$man<command
name>
Example:
$man who
Usage
of Directory commands:
1. pwd command:
It
tells us the full path from the current directory
Format:
$pwd
2.
ls command:
The
ls command displays the list of files in a current directory
Format:
$ls
The ls command comes with
different options. Some of them are given here,
|
ls-l
|
List files in login format. The
files are displayed along with there mode, number
of links, owner of files, file
size, modification date and time of file name
|
|
ls-t
|
List in order of last
modification time(most recent file)
|
|
ls-a
|
List all entries, including
hidden files
|
|
ls-b
|
List directory files instead of
contents
|
|
ls-p
|
Put a slash after each
directory
|
|
ls-u
|
List in order of last access
time
|
3.
mkdir command :
This command helps us to make a directory
Format:
$mkdir <directory name>
Example: mkdir cape
4. cd Command:
This
command helps us to change from working directory to any other directory specified
Example: Assume that you are working in
the directory path/user/you
$mkdir
book This makes a new
directory
$cd
book Used to change
the directory
$pwd Go to it /user/you/book
$cd.. This is used to move
up one level in file system.
$cd..
$pwd
/user/you
$cd This helps to return
to home directory.
5. rmdir Command:
This command is used to
remove a directory specified in the command .
Format:
$rmdir<directory name>
Example:
$rmdir book
Usage of file
command:
1) cat command:
This
command helps us to count the content of the file we specify. If we don’t specify the name of the file ,it
takes input from standard input.
Format
: $cat [path] filename
Example:
$cat xyz
Example:
$cat cape1
Have a nice day
Ctrl+l
2) cp Command:
This command helps us to create the
copies of a ordinary file.
Format :
$cp[path]sourcefilename[path]destinatiosnfilename
Example:
$cp cape1 cape2
3) ln Command:
This
command is used to establish a additional filename for the same directory file.
Format : $ln oldfilename new filename
Example:
$ln cape1 cape2
4) mv Command:
This command is used to move the
contents from one file to another file.
Format : $mv Source
Destination
Example: $mv
cape1 cape2
5) rm Command:
This
command is used to remove one or more files from a directory. This can be
used to delete all file as well as the
directory.
Format:
$rm [path] file
6) echo Command:
This command is used to display on
the screen.
Format : $echo “Message”
Example:
$echo “UNIX”
UNIX
7) read Command:
This
command is used in shell script. This command waits for the user to in pact
the value of the variable.
Format : $read variable
name
Important Keys
to Remember:
Enter
Key -Execute command in the escape model &
start a new line in the insert
mode.
Esc Key -Return
the vi editor to the command mode.
“/” -Helps
to search for a particular string with in the file.
“?” -Works the same way as “/”
“:” -Used
when we want to specify a command.
Three modes:
1) Esc mode.
2) Insert mode.
3)
Command mode.
Esc mode:
Movement of the
Cursor:
h or backspace:left
l or spacebar
:right
k or -
:up
j or +
:down
Some More Cursor
Movements:
w - Moves
forward by word.
b - Moves
backward by word.
e - Last
character of the word.
^ - Beginning
of the line.
$ - End
of the line.
L - Last
line of the file.
Screen Commands:
Ctrl+F - moves
forward direction by screen.
Ctrl+B - moves
backward direction of the screen.
Ctrl+D - moves
the cursor half of the screen in backward direction.
Ctrl+U - moves
the cursor half of the screen in forward direction.
i/I - change
to insert mode.
Insert mode:
I - invokes
insert mode and insertion takes place at the beginning.
a - used
for appending the text. Text is appended after the cursor position.
A - Used
for appending the text. Text is appended at back end of the line.
O - Allows
insertion by creating a blank line above the current line.
o - Allows
insertion by creating a blank line below the current line.
R - It
overwrites from current cursor position.
Command mode:
Esc+: -change to command mode.
Deleting data:
:u - undo all commands used in command prompt.
:set
number - set the line number.
:2Jo - used to join operation.
:2co7 - second
line is copied after seventh line.
:1,3co8 - first,second,third lines are copied after eighth line.
:3mo7 - move
third line after seventh line.
:2d - to delete the second line.
:2,5d - to delete the set of lines.(2,3,4&5)
How to quit vi
editor:
:q! - quit
without writing the changes into disk file.
:wq - quit
after writing the changes to the disk file.
Esc mode-deleting
datas:
dd - delete
the line in which cursor position.
dw - delete
the single word.
x/del - to
delete the single character at the cursor position.
X - delete
the single character before the cursor position.
RESULT:
Thus
the basic UNIX commands were studied and executed
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