Notes

simple calculator
echo "Enter Two numbers : "
read a
read b

# Input type of operation
echo "Enter Choice :"
echo "1. Addition"
echo "2. Subtraction"
echo "3. Multiplication"
echo "4. Division"
read ch

# Switch Case to perform
# calculator operations
case $ch in
1)res=`echo $a + $b | bc`
;;
2)res=`echo $a - $b | bc`
;;
3)res=`echo $a * $b | bc`
;;
4)res=`echo "scale=2; $a / $b" | bc`
;;
esac
echo "Result : $res"



Program in UNIX to convert Kilometers and print this distance in meters, feet, inches and centimeters.
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"


EVEN OR ODD IN SHELL SCRIPT:
HOW TO FIND A NUMBER IS EVEN OR ODD IN SHELL SCRIPT
# WRITTEN BY SURAJ MAITY
# TUTORIALSINHAND.COM
clear
echo "---- EVEN OR ODD IN SHELL SCRIPT -----"
echo -n "Enter a number:"
read n
echo -n "RESULT: "
if [ `expr $n % 2` == 0 ]
then
echo "$n is even"
else
echo "$n is Odd"
fi

Shell Script to Check if the Current Year is Leap Year or Not
leap=$(date +"%Y")
echo taking year as $leap
if [ `expr $leap % 400` -eq 0 ]
then
echo leap year
elif [ `expr $leap % 100` -eq 0 ]
then
echo not a leap year
elif [ `expr $leap % 4` -eq 0 ]
then
echo leap year
else
echo not a leap year
fi


Factorial of a number using while loop - Shell Script
echo "Enter a number"
read num

fact=1

while [ $num -gt 1 ]
do
fact=$((fact * num)) #fact = fact * num
num=$((num - 1)) #num = num - 1
done

echo $fact


How do I find prime number using Shell Script
#!/bin/bash
prime_1=0
echo "enter the range"
read n
echo " Primenumber between 1 to $n is:"
echo "1"
echo "2"
for((i=3;i<=n;))
do
for((j=i-1;j>=2;))
do
if [ `expr $i % $j` -ne 0 ] ; then
prime_1=1
else
prime_1=0
break
fi
j=`expr $j - 1`
done
if [ $prime_1 -eq 1 ] ; then
echo $i
fi
i=`expr $i + 1`
done


Fibonacci Series in Bash
# Program for Fibonacci
# Series

# Static input fo N
N=6

# First Number of the
# Fibonacci Series
a=0

# Second Number of the
# Fibonacci Series
b=1

echo "The Fibonacci series is : "

for (( i=0; i<N; i++ ))
do
echo -n "$a "
fn=$((a + b))
a=$b
b=$fn
done
# End of for loop


Shell Script to Sort Number in Descending Order
#!/bin/bash
echo "enter maximum number"
read n
# taking input from user
echo "enter Numbers in array:"
for (( i = 0; i < $n; i++ ))
do
read nos[$i]
done
#printing the number before sorting
echo " Numbers in an array are:"
for (( i = 0; i < $n; i++ ))
do
echo ${nos[$i]}
done
# Now do the Sorting of numbers
for (( i = 0; i < $n ; i++ ))
do
for (( j = $i; j < $n; j++ ))
do
if [ ${nos[$i]} -lt ${nos[$j]} ]; then
t=${nos[$i]}
nos[$i]=${nos[$j]}
nos[$j]=$t
fi
done
done
# Printing the sorted number in descending order
echo -e "nSorted Numbers "
for (( i=0; i < $n; i++ ))
do
echo ${nos[$i]}
done


#
#Write a script to display the name of all executable files in the given directory
#
clear
echo -n "Enter name of the directory :"
read directory

if [ ! -d $directory ]
then
echo "Directory not exist"
else
count=0
echo "Files with executable rights are"
#ONE SOLULTION IS
# for i in `ls $directory`
# do
# if [ -x $directory/$i ]
# then
# echo $i
# fi
# count=$(echo count + 1 | bc -l)
# done
for i in $(find $directory -type f -perm +111)
do
echo $i
count=$(echo count + 1 | bc -l)
done
if [ $count -eq 0 ]
then
echo "No files found with executable rights"
fi
fi


write a shell script to fetch the data from a file and display data into another file in reverse order.
if [ -f $fileName ]
then
str=`cat $fileName`

len=`echo $str|wc -c`

i=$len
while [ $i -ge 1 ]
do
temp=$temp`echo $str|cut -c $i`
i=`expr $i - 1`
done

echo $temp>Result_ex2f.txt
cat Result_ex2f.txt

else
echo "file [ $fileName ] not exist in c "
pwd
fi