ankur13secret · January 5, 2016 06:00
diff --git a/Bash.txt b/Bash.txt
 Bash [Bourne Again Shell]
 Bourne Means Boundary
 It is named so, because it supports user interaction and again a user can only interact with the script if it will wait for user. 

 Bash supports two modes 
 1. Interactive Mode(waits for user command, if required) &,
 2. Non-Interactive Mode

 File Descriptors are basically used to give instructions from outer world, e.g keyboards
 There are basically three types of file descriptors:-
 1. File Descriptor 0 : is called as standard input. This is where most process receives there input from input "connected"
 2. File Descriptor 1 : is called as standard output. This is where most process sends the output. By default, it is connected to the display for output.
 3. File Descriptor 2 : is called as standard error. This is where most process sends there error and informational messages. By default, it is connected to standard error which is connected to the display.
 Even the total number of descriptors are not cnstant and it may increase as per the requirement.

 Program : A program is a set pre-written set of instructions that can be executed by your system's kernel. A program gives kernels a direct instructions to execute.
 Kernel : A kernel is also technically a program, but the one that continously runs and communicates with hardwares.
 Streams : The flow of informations between files,devices and processes is called as streanms.

 What's a bash script? : It's a file with bash code in it that can be executed by the kernel just like any other program on your 
 computer. In essence, it is a program in itself, although it does need the bash interpreter to do the work of translating the 
 bash language into instructions the kernel understands.

 HashBang :  It tells the kernel what interpreter it needs to use to understand the language in this file, and where to find it. We call it a 
 "hashbang" because it always begins with a "hash" # followed by a "bang" !.

 A HashBang should be followed by a path which understand the way to run the scirpt file. Usually, we refer to /usr/bin/env which donot contain the logic to understand the script but it contains the path to the script.
	Bash [Bourne Again Shell]
	Bourne Means Boundary
	It is named so, because it supports user interaction and again a user can only interact with the script if it will wait for user.

	Bash supports two modes
	1. Interactive Mode(waits for user command, if required) &,
	2. Non-Interactive Mode

	File Descriptors are basically used to give instructions from outer world, e.g keyboards
	There are basically three types of file descriptors:-
	1. File Descriptor 0 : is called as standard input. This is where most process receives there input from input "connected"
	2. File Descriptor 1 : is called as standard output. This is where most process sends the output. By default, it is connected to the display for output.
	3. File Descriptor 2 : is called as standard error. This is where most process sends there error and informational messages. By default, it is connected to standard error which is connected to the display.
	Even the total number of descriptors are not cnstant and it may increase as per the requirement.

	Program : A program is a set pre-written set of instructions that can be executed by your system's kernel. A program gives kernels a direct instructions to execute.
	Kernel : A kernel is also technically a program, but the one that continously runs and communicates with hardwares.
	Streams : The flow of informations between files,devices and processes is called as streanms.

	What's a bash script? : It's a file with bash code in it that can be executed by the kernel just like any other program on your
	computer. In essence, it is a program in itself, although it does need the bash interpreter to do the work of translating the
	bash language into instructions the kernel understands.

	HashBang : It tells the kernel what interpreter it needs to use to understand the language in this file, and where to find it. We call it a
	"hashbang" because it always begins with a "hash" # followed by a "bang" !.

	A HashBang should be followed by a path which understand the way to run the scirpt file. Usually, we refer to /usr/bin/env which donot contain the logic to understand the script but it contains the path to the script.