METACHARACTERS OF UNIX

METACHARACTERS OF UNIX:

Metacharacters are special characters. The shell understands and interprets these

metacharacters in a special way.

*-specifies number of characters

?-specifies a single character

$ ls[t]*

List the files whose names begin with 't'

$ ls [a-m]*

List the files whose names begin with alphabets from 'a' to 'm'

PLAYING WITH FILES

PLAYING WITH FILES:

cp:

The cp command is used to copy the contents of one file to another and copies

the file from one place to another.

Syntax:$cp old_file new_file

rm:

The rm command is used to remove or erase an existing file.

Syntax:$rm filename

mv:

The mv command is used to move a file from one place to another,it removes a

specified file from its original location and places it in specified.

Syntax:$mv old_file new_file

ls:

The ls command is used to view the contents of a directory.

Syntax:$ls

ls -a:

To list all the files in the current directory in alphabetical order ls command with

-a is used.

Syntax:$ls -a

wc:

The wc command is used to count the number of words,lines and characters in a file.

Syntax:$wc filename

Options Purpose

-l Used to display only number of lines

-w Used to display only number of words

-c Used to display only number of characters

DIRECTORY COMMANDS

DIRECTORY COMMANDS:

pwd:

The pwd command is provided to know the current working directory.

Syntax:$pwd

mkdir:

The mkdir is used to create an empty directory in a disk.

Syntax:$mkdir dirname

rmdir:

The rmdir is used used to remove a directory from the disk.

Syntax:$rmdir dirname

cd:

The cd command is used to move from directory to another.

Syntax:$cd program

tput clear:

This command is used to clear the screen.

Syntax:$tput clear.

BASIC COMMANDS

BASIC COMMANDS

FILE COMMANDS:

cat:

The cat command is used to create a file.

Syntax: $cat>filename

The cat command is also used to view the contents of a specified file.

Syntax:$cat filename

The cat command serves to 'concatenate' multiple files into a single file.

Syntax:$cat file1 file2>file3

INTRODUCTION TO UNIX OS

INTRODUCTION TO UNIX OS

OPERATING SYSTEM:

It is the set or component of programs which are used to manage or controls the hardware as well as coordinates the applications.

THE UNIX OPERATING SYSTEM:

UNIX is an increasingly popular operating system. Unix operating is like a layer between the hardware and the applications that run on the computer. It has functions that

manage the hardware and functions that manage executing applications. The part of UNIX that

manages the hardware and the executing processes is called Kernel.

FEATURES OF UNIX:

• Multitasking

• MultiuserCapability

• Security

• Portability

• Communication

• Programming Facility

ADVANTAGES OF UNIX:

• UNIX allows only authorized users to modify files and directories.

• UNIX allows only System Administrators to make changes in System

  configuration files.

• UNIX is very stable Operating system.

• UNIX can be loaded to any type of Computer Hardware.