Mathematical Aspect of Linux Shell Programming – Part IV

In this post I will be discussing the Scripts from
the Mathematical and Number point
of view. Although I have posted a more complex script (Simple Calculator)
in the previous post, but on a user part it was difficult to understand and hence I thought to make you people learn the other useful side of learning in small packets.

Prior to this article, three article of Shell Scripting Series are published and they are:

Understand
Linux Shell and Basic Shell Scripting – Part I

5
Shell Scripts to Learn Shell Programming – Part II

Sailing
Through The World of Linux BASH Scripting – Part III

Let’s start the further learning process with some new exciting scripts, start withMathematics scripts:

Script 1: Additions

Create a file “Addition.sh” and chmod
755 to the script as described in previous post and run it.

#!/bin/bashecho “Enter the First Number: ” read a
ter the Second Number: ”
read b echo “E
n
x=$(expr "$a" + "$b")
echo $a + $b = $x

Sample Output

[root@tecmint ~]# vi Additions.sh[root@tecmint ~]# chmod 755 Additions.sh[root@tecmint ~]# ./Additions.sh

nter the Second Number: ”
“Enter the First Number: ”
12
“
E13
13 = 2512 +

Download
Additions.sh

Script 2: Substraction

#!/bin/bashecho “Enter the First Number: ” read a
ter the Second Number: ”
read b echo “E
n
x=$(($a - $b))
echo $a - $b = $x

Note: Here we replaced the expr and
let the mathematical calculation be performed in shell.

Sample Output

[root@tecmint ~]# vi Substraction.sh[root@tecmint ~]# chmod 755 Substraction.sh[root@tecmint ~]# ./Substraction.sh

r the Second Number: ”
20 “Enter the First Number: ”
13
“Ent
e
- 20 = -71
3

Download
Substraction.sh

Script 3: Multiplication

So far you would be enjoying a lot, learning scripts in such an easy way, so the next in chronological order is Multiplication.

#!/bin/bashecho “Enter the First Number: ” read a
ter the Second Number: ”
read b echo “E
n
ho "$a * $b = $(expr $a \* $b)"e
c

Note: Yup! Here we didn’t put the value of multiplication in a variable but performed it directly in output statement.

Sample Output

[root@tecmint ~]# vi Multiplication.sh[root@tecmint ~]# chmod 755 Multiplication.sh[root@tecmint ~]# ./Multiplication.sh

the Second Number: ”
11
1“Enter the First Number: ”
11
“Enter
1 * 11 = 121

Download
Multiplication.sh

Script 4: Division

Right! Next is Division, and again it is a very simple script. Check it Yourself.

#!/bin/bashecho “Enter the First Number: ” read a
ter the Second Number: ”
read b echo “E
n
ho "$a / $b = $(expr $a / $b)"e
c

Sample Output

[root@tecmint ~]# vi Division.sh[root@tecmint ~]# chmod 755 Division.sh[root@tecmint ~]# ./Division.sh

Enter the Second Number: ” “Enter the First Number: ”
12

“
3
3 = 412 /

Download
Division.sh

Script 5: Table

Fine! What after these basic mathematical operation. Lets write a script that prints table of any number.

#!/bin/bashecho “Enter The Number upto which you want to Print Table: ” read n
i=1
while [ $i -ne 10 ]
do
i=$(expr $i + 1)
table=$(expr $i \* $n)
echo $table
done

Sample Output

[root@tecmint ~]# vi Table.sh[root@tecmint ~]# chmod 755 Table.sh[root@tecmint ~]# ./Table.sh

ou want to Print Table: ”
29
58
87
116
145
174
20“Enter The Number upto which
y3
232
261
290

Download
Table.sh

Script 6: EvenOdd

We as a child always have carried out calculation to find if the number is odd or even. Won’t it be a good idea to implement it in script.

#!/bin/bashecho "Enter The Number" read n
pr $n % 2)
if [ $nnum=$(e
xum -eq 0 ]
then
ber"
else
echo "is a Oecho "is a Even Nu
mdd Number"
fi

Sample Output

[root@tecmint ~]# vi EvenOdd.sh[root@tecmint ~]# chmod 755 EvenOdd.sh[root@tecmint ~]# ./EvenOdd.sh

NumberEnter The Number
12
is a Even

[root@tecmint ~]# ./EvenOdd.sh
Enter The Number
11
is a Odd Number

Download
EvenOdd.sh

Script 7: Factorial

Next is to find the Factorial.

#!/bin/bash echo "Enter The Number" read a
fact=1
]
do
fact=$(exprwhile [ $a -ne
0 $fact \* $a)
a=$(expr $a - 1)
done
factecho
$

Sample Output

[root@tecmint ~]# vi Factorial.sh[root@tecmint ~]# chmod 755 Factorial.sh[root@tecmint ~]# ./Factorial.sh

Enter The Number
12
479001600

You may now relax with a feeling that calculating 12*11*10*9*7*7*6*5*4*3*2*1 would be more difficult than a simple script as produced
above. Think of the situation where you require to find 99! or something like that. Sure! This script will be very much handy in that
situation.

Download
Factorial.sh

Script 8: Armstrong

Armstrong Number! Ohhh You forget what an Armstrong
Number is. Well an Armstrong number of three digits is an integer such that the sum of the cubes of its digits is equal to the number itself. For example, 371 is
an Armstrong number since 3**3 + 7**3 + 1**3 = 371.

#!/bin/bash echo "Enter A Number" read n
arm=0
[ $n -netemp=$n
while
0 ]
do
% 10)
arm=$(exprr=$(expr $
n $arm + $r \* $r \* $r)
cho $arm
if [ $arn=$(expr $n / 10)
done

em -eq $temp ]
then
echo "Armstrong"
else
echo "Not Armstrong"
fi

Sample Output

[root@tecmint ~]# vi Armstrong.sh[root@tecmint ~]# chmod 755 Armstrong.sh[root@tecmint ~]# ./Armstrong.sh

gEnter A Number
371
371
Armstro
n

[root@tecmint ~]# ./Armstrong.sh
Enter A Number
123
36
Not Armstrong

Download
Armstrong.sh

Script 9: Prime

The last script is to distinguish whether a number is prime or not.

#!/bin/bash echo “Enter Any Number”read n
i=1
c=1
$n ]
do
i=$(expr $iwhile [ $i -le
+ 1)
r=$(expr $n % $i)
expr $c + 1)
fiif [ $r -eq 0 ]
then
c=$
(
done
if [ $c -eq 2 ]
then
echo “Prime”
else
echo “Not Prime”
fi

Sample Output

[root@tecmint ~]# vi Prime.sh[root@tecmint ~]# chmod 755 Prime.sh[root@tecmint ~]# ./Prime.sh

Prime”“Enter Any Number”
12

“Not

Download
Prime.sh

That’s all for now. In our very next article we will be covering other mathematical programs in the shell Scripting programming language. Don’t forget to mention your views regarding article in the Comment section. Like and share
us and help us spread. Come Visitingtecmint.com for News and
articles relating to FOSS. Till then Stay tuned.