Linux Command Line Tutorial For Beginners 33 - How to Run multiple Terminal Commands 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
to run two or more terminal commands at
once in Linux so till now we have seen
how we can you know use commands but we
haven't seen how we can combine two
commands and run them together and this
is what we are going to see in this
video so there are few options we can
use to combine commands so the first
command or first option which we can use
to combine command is semicolon and I am
going to tell you how this works so
whenever you want to combine command for
example I want to use LS command and I
also want to know the present working
directory so I am going to use PWD
command and in between I have used this
semicolon right and this is going to
combine these commands and then it is
going to show us the output right and I
am going to just press ENTER and this is
what the output is so first of all it
has you know given us the output for the
LS command which is this output and then
it has executed the PWD command which is
this output right so this is the output
from the PWD command
and this is the output from the you know
LS come on so in this way you can you
know combine these commands using
semicolon right we can also execute some
other command for example in the last
videos I have shown you how to use date
command and Cal command and let us say
we also you want to use PWD this time
also right so I am going to just press
ENTER and now it shows the first of all
that gate if this come on then the
calendar which is by this command and
then the present working directory which
is by this command right now one thing
to note here is whenever you use semi
: then for example one command is wrong
so what I am going to do first is for
example I want to give this command Cal
which is not existing so it is going to
give us this kind of output right so
let's use this scale in between here so
instead of smaller letter Cal I'm going
to just use Cal in capital letters and I
am going to press ENTER here so you can
see what happened here
so first command is executed which is
going to give this output for us second
command doesn't really exist so it's
going to give us the error but it's also
going to go to the next command is going
to print the next command output which
is the present working directory right
so this command doesn't stop executing
command if one command fails right so
it's going to execute the next command
if the command in between also fails
right so this is the speciality of this
command so I am going to just clear the
terminal and then I am going to talk
about the second command the second
command to combine a few commands
together is using these ampersand symbol
mm puts in percent symbols right and
this is essentially is going to do the
same so for example I want to do LS once
again and then double ampersand I want
to do PW T and then once again mm % then
I want to see the date so I'm going to
give the date and for example I want to
see the calendar also so I am going to
give the CA el command and press ENTER
so it gives the same output so the
output first will be the LS and then the
present working directory then output
for the date and then the output for the
calendar right now one thing to note
here in both these combining command
with semicolon and these M percent is
the sequence of matters here so for
example
when I use a date semicolon Cal here
then first date will be executed and
then calendar will be executed so this
sequence matter so for example when you
do Cal and them date then it's going to
show the calendar first and then the
date okay and same is with the ampersand
also so instead of this semicolon when
you use ampersand is going to show us
the calendar first and then the date and
when we use date I am present Cal then
it's going to give us the you know this
date first and then the calendar okay
but what is the difference between these
two commands so let me clear the
terminal and then I'm going to show you
what is the difference between these two
commands okay so the difference between
these two command is whenever you use
this semicolon is going to run us every
command regardless of the success or
failure of the previous command right so
we have already seen for example we give
the wrong command which doesn't really
exist for example Cal here and then
semicolon date then first command fails
here but second execute so it doesn't
matter if first command is fail or the
command in between field is going to
execute all the command there right but
when you use the same thing with the
ampersand then whenever you know
previous command fails then it is going
to stop executing the next command so
when we use this you see it just give
the output that this command does not
exist and it doesn't go to the next
command which is date right we can once
again check this by typing PWD
ampersand for example once again capital
date here and then apus m % Cal here
right so it
was the output for the PWD and then the
next command doesn't really exist so
it's you know give the output command
doesn't exist and then it doesn't
execute the next command after the error
but with the semicolon it's going to
execute every command regardless the
previous command is failed or succeeded
okay so this is the difference between
these two command now we are going to
see the next option which is the or
option right so or you can use using
these double pipes here and this is how
you can use it so for example you use LS
and then you use or for example with
these pipes and then PWD and then press
ENTER and then what you see as an output
here is the output is the combination of
logical or here so if the first command
is successful it's not going to go to
the second comma right and then when the
same command I do with for example LS
capital LS and press Enter then it's
going to show you the output for the
second command right so once the first
command is not successful the or will
allow this
you know these commands go to the next
command and it's going to execute the
next command so it's like a logical or
operation so if the first command
execution fails then it's going to go to
the next command right so this is how
you can combine commands in Linux so
what we have learned so for example of
what we have learned is for example we
have to command a and B then whenever we
use semicolon then run a and then B
regardless of the success or failure of
a right so a and B are going to run
regardless a fails or not right and we
have also seen the ampersand and in this
case if a fails then B is
not going to execute right now however
is the or operator and in this case B is
only going to be executed if a fails
right if a succeeds then B will not be
executed so these are the few options
you can use to combine command in Linux
I hope you have enjoyed this video
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now