Linux - Variables

so now here in this particular video I'm

going to talk about some of the

variables

now what this variables are by name

itself we come to know the data which is

going to vary which is going to change

now here I'm going to use some variables

which why default you have into the

Linux operating system and the value of

this particular fryer or a particular

data of this particular file gets

changed so basically you have a profile

slash etc' slash profile when your

operating system gets started first your

system will check what you have in the

profile

nobody first want this profile content

when you get login what kind of desktop

you got what the services should be

started when you get started so

everything will be listed into that

profile and by default this file is

hidden into all the particular home

directories and your system directory so

when your system file or when your

system starts first it will search for

your profiles file that you have set

anything to be started on this startup

while your system is getting started or

you have some of this script file which

is located over here the script file are

nothing but the automated some commands

all automated some programs you have a

fight so it will check into this slash

it is a slash profile when your system

gets started if suppose it doesn't find

anything so there is nothing such like

it will provide you another because this

profile will only contain what you need

to start and what are the services you

have started while your system is

getting started if you don't find

anything what it will do it will skip

that file and then it will go to the

home directory of the user for looking

at what the user wants when it gets

local so again it will move into slash

home slash profile so slash home slash

profile will contain all the particular

user commands or all the particular

users shares or programs which that

particular user want to start again if

you would find anything the particular

program get started if it doesn't find

anything over here automatically it will

stop it over there itself or it will

skip it over there itself and then move

ahead and give the basic shell to your

particular profiles same way what this

plot file contains as I said it contains

your terminal you

such commands it will contains the type

of terminal you are going to use it

contains in which type of terminal you

are going to get long it or which we

have kept logged in same thing it will

also contain the directories list which

you already have now if suppose I want

when I get started or when I get login

in which directory I should move and

what are the directories I have created

it should be listed in to me I can also

put enter into my dot profile then also

add the variable or any particular data

which we feel that should get started

when your user get logged in so we can

also add those kind of data into the

profile which can vary or which can F

get affected while my system is getting

multiple time logged in so this is what

exactly dot profiles are now if I want

to check this dot profile file into a

particular home directory I need to move

into slash home and then again we need

to give the same command LS space hyphen

e it will show me this particular file

and let us check what this file contains

into our Linux terminal so as discussed

when your machine gets started it will

go for the profile generally we have

into this system variable or we could

say the variables which we have defined

you bring the system so if I want to

check all the variables which we have

that as well as an environment variables

so which we do not use on this shelf

what if we have you know declared into

the computer itself so that when it

starts it get access to all the

particular variables we have defined so

this are these some environment

variables which are by default defined

into the system so whenever your system

gets started it will check for all this

environment variables right like your

shell will always be been bash it serves

right your window will be the spot size

window ID will be this my size the

colors which you are going to follow

right and along with that it will show

you more of the details window path

which is the language you will be

following what is the you know a home

directory of this particular directory

so as I told you like all the particular

environment variables which are declared

it will check for each or everything

now let us have a look like what the

environment variable has been defined

into the slash home and your user

profile so as we know if I want to use

into the go into the user profile I'll

be using CD and intro so right now I'm

into my user profile that is home

trainer so if I give the command and I

won't be able to see any hidden files

and as discuss this files are by default

hidden into your profile so I'll given a

space - II and you can check please have

some read dot filenames this are your

hidden files so let us check this Aden

files by keeping come on Ln space hyphen

e so we can check the complete union of

the spots so this is your bash history

this is your bash logout bash profile so

this three files should really be have

right now right so starting with your

dot profile so dot bash profile if I

want to check the content of dash bash

profile what I'll be doing is I'll give

the command cat dot bash profile so you

know it should always follow with dot so

that comes to know it to the same father

so once you move into it you will find

that here some function has been called

and opposed that we have the user

variable which is the environment and

the starter programs we generally have

defined here so it is defining that we

need to move into the part where I'm

going to define the variable path so

whenever there is a variable declared

and it contains some values it will be

along with the dollar path so we are

going to call this particular value of

it

same way your dollar and whom so let us

check what this path contain so into any

variant of this year as this is an

environment variable you can get the

data outfit anywhere so you can check

I'm just calling this part and you are

going to get access to all the

particular you know path which we use

generally after we get login with this

particular user so this are the

directories these are the

of paths we can follow this particular

user can move and then get access to

your commands

so same VAP we also have dollar home

into capital case which is defined over

here so I need to check what this dollar

home contains so it contains your user's

home directory information right so when

the user get logins so it get access to

all this particular directory so I can

move into all the directories along with

that he will be able to move directly

into the bash so if you do not have this

command or if we do not declare this

your system your you know user want to

be able to get login directly into the

user profile so this is what the

environment you know variables we use

into the unite profile as well same way

we also have some files which we are

going to see that is your

Alice space - a which is your dot bash

history so dot bash history is generally

used to store your all the commands

which we have used using this particular

user so you can check into dot bash

history it will have the collection of

all the commands we have you know used

till now so I'll just give more so that

I can look at out completely so you can

see I started with PWD command and then

as the tutorial I have created I have

started using a different commands here

so it will keep a list of all my

commands which I have used using this

particular user

same way it also contains um no command

so that we can get all the particular

history pulled over here by using

history so I can see it will show you

along with the serial number right so

these are the commands which we have

used so now even it will collect the

history command which we have used right

so this is not how generally your

environment to variable speech and

really have and mostly if you want to

add any particular SDKs and you want to

define the path of those SDKs into your

environment variable you have to define

it into it so this is what exactly we

have into your environment variable and

dot profile contains and also we have a

file called as dot bash logout so once

we log out what should happen it

contains some scripts here you can come

to know while I move into the log out

file so you can find it contains a bash

logout come on that's it right so this

is how generally we create the

environment variables and we can check

which are the environment variables are

by default declared into the machine now

same way if I want to define any

environment variable of my own I can

also define it by using E and V and you

can define the name of our and moromete

variable so if suppose I want to define

the name as trainer

so you can see this one environment

variable is added and find the name

trainer has been added here so this is

how we had can declare your own

environment variables same way if I want

to define some pot

so I can also define the park in such a

way

et Cie slash

passwd as well so we it has by default

added into the path right so this is how

generally we can add you know the part

and then we can add the environment

variables into the system