Linux Command Line Tutorial For Beginners 20 - Introduction to Bash Scripting Video Lecture | Complete Linux Course: Become a Linux Professional - Software Development

hello guys welcome to the next video on
Linux command line tutorial for
beginners in this video we will see how
we can create our script in Linux and we
will also see how we can execute our
script and we will learn how we can
write for example our first hello world
script now scripting in general is
really you know deep concept and I can
make a separate tutorial about scripting
itself right so in this video I just
want to give you the brief introduction
about scripting and how you can use
scripting so that you can build on that
knowledge and you can you know learn ago
about scripting in different video or
different you know so from this
different source right so first of all
what is a script a script is a text file
that contains a sequence of command for
our Linux based operating system so
let's see how we can create a script so
I'm going to open our terminal first of
all and in this terminal first of all
let's say we want to create a script on
the desktop so I will just change the
directory to the desktop and then I will
use our Nano editor or creating a script
so for creating a script you just need
to write Nano and then the script name
so for example I will name my script as
my script itself now it's enough to give
this name my script here but it's a good
practice to give an extension of SH here
for you know just showing the user that
it's a script okay so I'm just adding
the extension here but if you don't add
this extension here it will work fine so
it's so not going to be different if you
don't add this extension
now first of all we need to know where
our Bash is located on our system so
what I'm going to do is before creating
a file or let's just create a file and
then
we are going to see for them so nano and
then the name of the script and placenta
and it's going to open this kind of
editor to you right now first line which
you write in a script is this line which
you need to use or it's a good practice
to use this so first is you need to
write hash and then this exclamation
mark which is called hash Bank and then
the location of your bash now what I'm
going to do is I'm going to open a
different terminal and then we will see
the location of our bash where is our
bash right now what we are going to do
is just to which and then just write
bash here okay and then press ENTER and
it gives this answer so this which
command we are going to learn later what
is this which command and what it does
is but just open a new terminal and just
write which bash and it's going to give
you the location where bash is located
so this is the location so just take
this location and after this hash Bank
which we have written here you need to
write this location so /bin for slash
bash okay which is this location here
okay so we just needed to know the
location and whatever the location is
you just need to write here after this
hash bang okay and now you can close the
other terminal so this tells the you
know interpreter that this is a script
which is using bash and then as I have
told you the script is a sequence of
commands so for example I can normally
write LS for listing for example let's
do long listing with this script first
of all right so just hash bang and then
the long listing which is which you
write on the terminal it will list out
the
of you know files or directory on your
terminals right now in order to save it
you just need to write ctrl o + + Enter
which will save it and then ctrl X to
exit so you can see here our script is
created now in order to execute the
script first of all let's see when we
execute it what happens so normally you
need to give the permission execute
permission to your script but if you do
it without giving the permission let's
see what happens so to execute a script
you just need to write dot forward slash
and then the name of your script
something like this so my script right
so just write my script here dot SH ok
and then when you execute it it says
permission denied because your script
doesn't have the execute permission when
you create it ok so in order to give the
execute permission you need to just give
the execute permission to it so you can
just write chmod plus X for giving the
execute permission to use a group and
the others and then your script name for
example ok and then press enter and now
your script has the execute permission
right so in the last 3 video we have
been learning how to give the permission
to the script and that's why I'm I was
you know creating those video to you
know let you know how you can change the
permission of a file now this will
change the permission of a file to the
execution so you can execute this script
by giving this permission now once again
when we do dot the forward slash and
then the script name and press Enter
what it does is it's going to list out
the long listing of your desktop right
so you can see let me just make it a
little bit bigger and once again execute
it again and you can see it has done the
long listing off on the desktop so you
can
we have three files on the desktop and
each have their own permission so first
as the directory other is the file dot
txt and third one is the my script dot
SH which have all the execute permission
here okay so this is a simple for
example hello world script you can write
us let's modify our script and let's see
what else we can do
so single command we can know uhm you
know you can ask why we need script for
executing a single command so let's go
to the script
again so I will just write Nano and then
my script and this is a very basic
example I have given you but with this
scripting you can execute all you know
sequence of common not only one command
but for example let's do for example I
will do LS and then I'll echo something
and let's echo hello world here ok and
then I will just save it ctrl o and
press ENTER and then control X and once
again when I execute this script it
first of all list out the contents of
the directory and then it prints the
hello world which is using the echo
command right now I have shown you in
the echo command tutorial that we can
also create a variable in you know you
for using it in the echo so for example
I will create a variable let's say it's
called string is equal to and I will
assign something to it let's say hello
world itself something like this ok and
with echo you can just call this
variable by using this dollar symbol so
just write something like this ok so
swing and using the the dollar symbol
before the variable name
you can echo it okay so I will just save
it and the presenter executes I will
exit it and then once again execute the
command and it's doing the same so you
can see here in this script we are
performing the you know cease of command
and this is what scripting is so you can
write you know sequence of you know
command here and execute it and
scripting is much advanced than this so
it has a functions and it has loops and
if conditions so you know it's a
different topic to learn scripting but I
have wanted to know let you know that
this kind of scripting exists so you can
build on this knowledge and learn about
scripting there is it so really you know
important if you want to pursue your
career in Linux for example right so I
hope you have enjoyed this video please
rate comment subscribe and bye for now