Basic Shell scripts for Operating system

(1) Write a shell script to generate mark sheet of a student. Take 3 subjects, calculate and display total marks, percentage and Class obtained by the student.

clear

echo "Enter the three subject marks for the student"

read m1 m2 m3

sum1=`expr $m1 + $m2 + $m3`

echo "Sum of 3 subjects are: " $sum1

per=`expr $sum1 / 3`

echo " Percentage: " $per

if [ $per -ge 60 ]

then

echo "You get Distinction”

elif [ $per -ge 50 ]

then

echo “You get First class”

elif [ $per -ge  40 ]

then

echo "You get Second class"

else

     echo "You get Fail"

fi

OUTPUT

     Enter the three subject marks for the student

     45 

     35

     45

     Sum of 3 subjects are: 125

     Percentage : 41.67

You get second class

(2) Write a shell script to find factorial of given number n.

clear

echo "enter a number"

read num

fact=1

while [ $num -ge 1 ]

do

fact=`expr  $fact\* $num`

num=’expr $num – 1’

done

echo "factorial of $n is $fact"

Output:

enter a number

4

Factorial of 4 is 24

(3) Write a shell script which will accept a number b and display first n prime numbers as output.

echo  "Enter a number: "

read num

i=2



while [ $i -lt $num ]

do

  if [ `expr $num % $i` -eq 0 ]

  then

      echo "$num is not a prime number"

      echo "Since it is divisible by $i"

      exit

  fi

  i=`expr $i + 1`

done



echo "$num is a prime number "

Output:

Enter a number: 1879

1879 is a prime number

Enter a number: 119

119 is not a prime number

(4) Write a shell script which will generate first n fibonnacci numbers like: 1, 1, 2, 3, 5, 13,…

clear

  echo "How many number of terms to be generated ?"

  read n

  x=0

  y=1

  i=2

  echo "Fibonacci Series up to $n terms :"

  echo "$x"

  echo "$y"

  while [ $i -lt $n ]

  do

      i=`expr $i + 1 `

      z=`expr $x + $y `

      echo "$z"

      x=$y

      y=$z

  done

output:-

How many number of terms to be generated ?

5

0,1,1,2,3

(5)Write a menu driven shell script which will print the following menu and execute the given task.

 MENU

 Display calendar of current month

 Display today’s date and time

 Display usernames those are currently logged in the system

 Display your name at given x, y position

 Display your terminal number

 Exit

clear

while(i==0)

do

{

echo"enter  choice from menu"

echo"1. Display calendar of current month

                 2.Display today’s date and time

                 3.Display usernames those are currently logged in the system

                4. Display your name at given x, y position

                5. Display your terminal number

                6. Exit "

read choice

case "$choice" in

1)cal;;

2)date;;

3)who;;

4)tput cup 4 5

   whoami;;

5)tty;;

6)exit;;

output:-

enter  choice from menu

1. Display calendar of current month

                 2.Display today’s date and time

                 3.Display usernames those are currently logged in the system

                4. Display your name at given x, y position

                5. Display your terminal number

                6. Exit "

5

/dev/pts/11