Shell Scripting Tutorial-22: Count The Number of Command Line Arguments Using $# Video Lecture | Shell Scripting: Discovering to Automate Command-Line Tasks - Back-End Programming

hello guys my name is mother and welcome
to my channel this is the twenty second
tutorial in the series of tutorials on
UNIX shell programming now this is going
to be a short video and we are just
gonna check out how to find out the
number of positional parameters that
have been set through either the set
command or through the command line
arguments that have been passed through
a script file so what I'm gonna do is I
have my terminal opened up here and I'm
gonna just execute set with simple
sentence something like Tom Hanks is my
favorite actor and when I press the
Enter key
how many positional parameters have been
said well daughter one would get Tom and
actor being the sixth word in the
sentence would be stored in daughter six
so basically six positional parameters
have been used to set the statement now
if I wish to see the number of
parameters that have been set then there
is a special parameter called taller
hash and that's dollar and the pound
symbol and that is the parameter in
which the number gets stored so if I
simply echo that out echo dollar hash
and if I press the Enter key then I see
that UNIX displays six on screen so this
is a very useful concept and we can use
it for lot of interesting things and
this is something that we're going to
use in our next script file and I'm
gonna open my text editor and before I
type in text I'm gonna save this file as
I always do and I'm gonna call it SS
seven because this is a seven script
file now give it the thought SH
extension and I'll save it in my home
directory right now what I'm gonna do in
this file is I'm gonna use this program
to find out the number of files or
directories or all the items that I have
in my present working directory right
and it's going to be a very simple
script it's just gonna have one line in
it and I'll use the echo statement
because I'll be echoing the number out
on screen and I'm just going to type in
a set sentence
something like
the total number of items in the current
type three is equal to and I'm gonna put
my dollar hash parameter in in there now
save this file and I'll then get back to
my terminal I'll clear the screen for
you first and then I'll execute this
program using s H type in SS 7/3 SH
which is the name of my program and then
I have to give a command line argument
area here because in my script file as
you must have seen I haven't set
anything right so I cannot I haven't
said positional parameters yet I haven't
used the such statement so I'll be
passing command line arguments now when
we discuss the file command in I don't
know which tutorial but you know maybe
in the six or seven tutorial it seems
like a long time ago then I told you
guys that the significance of the
asterisk character in UNIX is that it
stands for everything that you have in
your diet tree right and I didn't lie
then and we actually saw that when we
executed file and file with the Astra
character then all the files and deities
in our current folder got displayed
right so if I just type in the Astra
character here then the script would
think that I basically wish to set the
positional parameters with the names of
the files and directories that I have in
my home folder which is my present
working directory right so if I press
the Enter key then I see that the total
number of items in the current directory
is 17 and if you would open the home
folder and if you would count the number
of items that you have then you would
obviously you know get the correct
number so there you go that's all I
wanted to talk about in this tutorial
and please subscribe to my channel and
thank you so much for watching this one
and I'll see you guys in the next
tutorial