echo "Student Marksheet"
echo "*****************"
echo "Enter Operating System Marks:"
read os
echo "Enter C++ Marks:"
read cpp
echo "Enter Java Marks:"
read java
echo "*****************"
total=`expr $os + $cpp + $java`
echo "Total Marks:" $total
percentage=`expr $total / 3`
echo "Percentage:" $percentage %
if [ $percentage -ge 60 ]
then
  echo "Class: First Class Distinction"
elif [ $percentage -ge 50 ]
then
  echo "Class: First class"
elif [ $percentage -ge 40 ]
then
  echo "Class: Second class"
else
  echo "Class: Fail"
fi

fact=1
read -p "Enter a number to find its factorial: " n

if [ $n -le 0 ]; then
  echo "Invalid number"
  exit 1
fi

a=$n
while [ $a -ge 1 ]; do
  fact=`expr $fact \* $a`
  a=`expr $a - 1`
done

echo "Factorial of $n is $fact"

read -p "Enter the value of n (or range): " n
echo "The prime numbers are: "
m=2
while [ $m -le $n ]
do
  i=2
  flag=0
  while [ $i -le `expr $m / 2` ]
  do
    if [ `expr $m % $i` -eq 0 ]
    then
      flag=1
      break
    fi
    i=`expr $i + 1`
  done
  if [ $flag -eq 0 ]
  then
    echo $m
  fi
  m=`expr $m + 1`
done

read -p "Enter the value of n (number): " n
x=0
y=1
i=2
echo "Fibonacci Series up to $n terms is : "
echo "$x"
echo "$y"
while [ $i -lt $n ]
do
  i=`expr $i + 1`
  z=`expr $x + $y`
  echo "$z"
  x=$y
  y=$z
done

1. Display calendar of current month

2. Display today’s date and time

3. Display user names those are currently logged in the system

4. Display your name at given x, y position.

5. Display your terminal number

echo "Select Anyone Option"
echo "**************************************************"
echo "1) Display Calendar of the current month"
echo "2) Display Today's Date and Time"
echo "3) Display Username of users currently logged in"
echo "4) Display your name at a given x,y position"
echo "5) Display your terminal Number"
echo "6) Exit"
echo "Enter your choice:"
read ch

case $ch in
1) cal ;;
2) date ;;
3) who ;;
4) row=$(tput lines)
   col=$(tput cols)
   echo "Terminal Window has Rows=$row Cols=$col"
   echo "Enter desired X,Y position"
   echo "X position="
   read x
   echo "Y position="
   read y
   echo "Enter the name"
   read name
   tput cup $x $y
   echo "$name" ;;
5) tty ;;
6) echo "Exit" ;;
*) echo "Enter a valid choice" ;;
esac

read -p "Enter the number of values you want to sort: " n

for ((i=0; i<$n; i++))
do
    read -p "Enter value of arr[$i]: " arr[$i]
done

for ((i=0; i<$n; i++))
do
    for ((j=0; j<$n-i-1; j++))
    do
        if [ ${arr[j]} -lt ${arr[$((j+1))]} ]
        then
            # Swapping
            temp=${arr[j]}
            arr[$j]=${arr[$((j+1))]}
            arr[$((j+1))]=$temp
        fi
    done
done

echo "Numbers sorted in descending order:"
echo ${arr[*]}

echo "Input your string without space"
read vstr
rvstr=""
for ((i=${#vstr}-1; i>=0; i--))
do
  rvstr="$rvstr${vstr:$i:1}"
done

echo "Input string was: $vstr"
echo "After Reversing String Is: $rvstr"

if [ "$vstr" = "$rvstr" ]
then
  echo "String Is Palindrome."
else
  echo "String Is Not Palindrome."
fi

# store day, month and year
dd=0
mm=0
yy=0
# store number of days in a month
days=0
# get day, month and year
echo -n "Enter day (dd) : "
read dd
echo -n "Enter month (mm) : "
read mm
echo -n "Enter year (yyyy) : "
read yy
# if month is negative (<0) or greater than 12
# then it is invalid month
if [ $mm -le 0 -o $mm -gt 12 ]; then
    echo "$mm is an invalid month."
    exit 1
fi
# Find out number of days in given month
case $mm in
    1) days=31 ;;
    2) days=28 ;;
    3) days=31 ;;
    4) days=30 ;;
    5) days=31 ;;
    6) days=30 ;;
    7) days=31 ;;
    8) days=31 ;;
    9) days=30 ;;
    10) days=31 ;;
    11) days=30 ;;
    12) days=31 ;;
    *) days=-1 ;;
esac
# find out if it is a leap year or not
if [ $mm -eq 2 ]; then # if it is feb month then only check of leap year
    if [ $((yy % 4)) -ne 0 ]; then
        : # not a leap year : means do nothing and use old value of days
    elif [ $((yy % 400)) -eq 0 ]; then
        # yes, it's a leap year
        days=29
    elif [ $((yy % 100)) -eq 0 ]; then
        : # not a leap year do nothing and use old value of days
    else
        # it is a leap year
        days=29
    fi
fi
# if day is negative (<0) and if day is more than
# that month's days then day is invalid
if [ $dd -le 0 -o $dd -gt $days ]; then
    echo "$dd day is invalid"
    exit 3
fi
# if no error that means date dd/mm/yyyy is a valid one
echo "$dd/$mm/$yy is a valid date"

echo "Enter the String"
a=$(awk 'BEGIN{ getline str; print toupper(str); }')
echo $a

echo -n "Enter distance in km : "
read km
m=`echo $km * 1000 |bc`
cm=`echo $m * 100 |bc`
ft=`echo $cm / 30 |bc`
in=`echo $cm / 2.5 |bc`
echo "Distance in meters : $m"
echo "Distance in feets : $ft"
echo "Distance in inches : $in"
echo "Distance in centimeters : $cm"

#!/bin/sh
a=10
b=20
val=`expr $a + $b`
echo "a + b : $val"
val=`expr $a - $b`
echo "a - b : $val"
val=`expr $a \* $b`
echo "a * b : $val"
val=`expr $b / $a`
echo "b / a : $val"
val=`expr $b % $a`
echo "b % a : $val"
if [ $a -eq $b ]
then
echo "a is equal to b"
fi
if [ $a -ne $b ]
then
echo "a is not equal to b"
fi

echo "---- EVEN OR ODD IN SHELL SCRIPT -----"
echo -n "Enter a number: "
read n
echo -n "RESULT: "
if [ `expr $n % 2` -eq 0 ]; then
    echo "$n is even"
else
    echo "$n is odd"
fi

echo "Enter Year"
read yr

if [ `expr $yr % 4` -eq 0 -a \( `expr $yr % 400` -eq 0 -o `expr $yr % 100` -ne 0 \) ]; then
    echo "Entered year is a leap year"
else
    echo "Entered year is not a leap year"
fi

for num in {1..300..2}
do
echo "Number: $num"
done

#!/bin/bash
for num in {2..300}
do
is_prime=true
for (( i=2; i<num; i++ ))
do
if [ $(($num%$i)) -eq 0 ]
then
is_prime=false
break
fi
done
if $is_prime
then
echo $num
fi
done