Shell Scripting Tutorial-48: Sleep while you are at work Video Lecture | Shell Scripting: Discovering to Automate Command-Line Tasks - Back-End Programming

hello guys my name is Martin and welcome
to my channel this is the 48 tutorial in
the series of tutorials on UNIX shell
scripting this tutorial is going to be a
short one and I'm just going to discuss
one command with you guys and that's the
sleep command and sleep is used to
produce time delays in the execution of
your shell scripts and without talking
about sleep much I just demonstrated to
you guys in a shell script so I have my
text editor here and I've saved this
file in the home folder it's called
sleep and has the extension SH and what
the script file is going to do is it's
going to ask the user to enter a
sentence and then it will save the
sentence or the input in a variable and
then it would use for loop to iterate
over the words in the variable and it
will display one word at a time on
screen but it's going to also produce a
delay between the printing of each word
right so firstly I'll use echo to ask
the user to enter a sentence enter a
sentence and the colon and the /c
sequence and then I'll use read to store
the input in a variable called STR right
now I'll type in the keyword for because
I'm going to use for loop 2 I trade over
the words in the sentence and then I'll
have to type in my control variable for
the loop which I'm going to call word
and then the keyword in and then the
sentence over which I want for to I
trade and since in this case you've
stored the input in the variable STR
I'll have to type in dollar st AR here
right on the next line I'll type in the
keyword do and that's to get in the for
block and inside the for block I'm just
going to use echo statement to display
the words in the sentence and the
command for that is going to be echo
space dollar world and in the first
iteration 4 is going to display the
first word in the sentence in the second
iteration or is going to display the
second word and this is going to happen
as many times as there are words in the
sentence that's stored in the variable
STR but as I said we are going to use
sleep in this shell script and sleep is
going to call
as a delay and I type in sleep space the
number of seconds by which I want each
iteration to be delayed right so the
first iteration is obviously not going
to have any delay because it's going to
print the message before uh you know it
encounters the sleep statement but
second iteration onwards sleep is going
to produce some delay for us and I'll
have to specify the number of seconds by
which I want the adorations to be
delayed and I'm just going to type into
here right and on the not on the next
line I'll type in the keyword done and
that will be you close my for loop and
with that my script is complete so I'll
bring up my terminal here and I'll
execute the script file by typing in SH
space sleep thought SH which is the name
of the file and when I press the Enter
key the shell asks me to enter a
sentence and I'll just type in something
random here like Al Pacino is my
favorite actor well is he how would you
guys know I don't know that myself but
he definitely is a legendary actor and
when I press the Enter key here then you
see that I see the word al immediately
but the remaining words in the sentence
are being displayed to me wet timelines
right so al was displayed and then the
shell waited for two seconds and then
Pacino was displayed and then celebrated
for two more seconds in the third word
is was displayed and that happened till
the last word in the sentence which is
act or God displayed right and once
actor was displayed the for-loop ran out
of words to I trade over and that's when
the script finished its execution and
the daughter prompt was returned back to
me so you can play with this script you
can you'll obviously have to type in the
code first and it's a pretty easy script
to understand so I'm not even going to
you know go over it again the only thing
that you have to remember the only new
thing that we've done in this script is
the sleep X command and if you type in
sleep X then what happens is sleep make
sure that the next thing that has to be
done in the shell script in this case it
was the next or loop iteration but if it
was something else for example if I had
another echo state
here or if I had something else then you
know that statements execution would be
delayed by as many seconds as you
specify so if you you know specify five
then the execution be delayed by five
seconds if it's stand and then so you
know that's what sleep does so anyway
thank you so much for watching this
tutorial I hope you guys had fun and
I'll see you in the next tutorial where
we will discuss something interesting
and important again please subscribe my
channel