test os in bash

gub@cseit:~$ ld
ld: no input files
gub@cseit:~$ cd Documents
gub@cseit:~/Documents$ mkdir Tushar
gub@cseit:~/Documents$ cd Tushar
gub@cseit:~/Documents/Tushar$ which bash >new.sh
gub@cseit:~/Documents/Tushar$ ls
new.sh
gub@cseit:~/Documents/Tushar$ chmod +x new.sh
gub@cseit:~/Documents/Tushar$ gedit new.sh
gub@cseit:~/Documents/Tushar$ gedit new.sh
gub@cseit:~/Documents/Tushar$ /new.sh
bash: /new.sh: No such file or directory
gub@cseit:~/Documents/Tushar$ ./new.sh



#!/bin/bash
echo -n "enter a number"
read n
for ((i=1;i<=n; i++))
do
echo "Output $i"
done

---------------------------------

#!/bin/bash
echo -n "enter a number"
read n
sum=0
for ((i=1;i<=n; i++))
do
sum=$((sum+i))
done
echo "Output is $sum"

----------------------------



Taking input in array :
>>>>>>>>>>>>>>>>>>>>>>

#!/bin/bash
echo -n "enter limit: "
read n
echo "Enter Numbers: "
for ((i=0;i<n; i++))
do
read a[$i]
done


##!/bin/bash
echo -n "enter limit: "
read n
echo "Enter Numbers: "

#!/bin/bash
 echo "Enter the first number :"
read a
echo "Enter the second number : "
read b

if [ $a -gt $b ]
then
num=$a
den=$b
else
num=$b
den=$a
fi
r=`expr $num % $den`

while [ $r -ne 0 ]
do
num=$den
den=$r
r=`expr $num % $den`
done

gcd=$den
lcm=`expr $a \* $b / $gcd`

echo " The LCM of $a and $b is : $lcm"
echo " The GCD of $a and $b is : $gcd"

leaf year...

echo "Enter Year:"
read y

year=$y

y=$(( $y % 4 ))
if [ $y -eq 0 ]
then
    echo "$year is Leap Year!"
else
    echo "$year is not a Leap Year!"
fi




prime number...

echo "Enter a number: "
read num
i=2
f=0
while [ $i -le `expr $num / 2` ]
do
if [ `expr $num % $i` -eq 0 ]
then
f=1
fi
i=`expr $i + 1`
done
if [ $f -eq 1 ]
then
echo "The number is composite"
else
echo "The number is Prime"
fi

Armstrong number or not...
echo "Enter a number: "
read c

x=$c
sum=0
r=0
n=0
while [ $x -gt 0 ]
do
r=`expr $x % 10`
n=`expr $r \* $r \* $r`
sum=`expr $sum + $n`
x=`expr $x / 10`
done

if [ $sum -eq $c ]
then
echo "It is an Armstrong Number."
else
echo "It is not an Armstrong Number."
fi

factorial number....
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



palindrome.....
echo "enter the string "
read name
name1=$(echo $name | rev)
if [ $name = $name1 ]
then
echo "$name is palindrome"
else
echo "$name is not a palindrome"
fi

sum of natural ...
 echo "Sum of n natural numbers \n”
echo "Enter the value of n "
read n
i = 0
sum = 0
while[$i –lt $n]
do
sum=’expr $sum + expr $i’
i = ‘expr $i + 1’
done
echo "Sum of n natural numbers are : $sum”

#shell script to check whether a number is positive or negative

echo "Enter a Number"
read num

if [ $num -lt 0 ]
then
    echo "Negative"
elif [ $num -gt 0 ]
then
    echo "Positive"
else
    echo "Neither Positive Nor Negative"
fi

odd or even....
echo -n "Enter numnber : "
read n

rem=$(( $n % 2 ))

if [ $rem -eq 0 ]
then
  echo "$n is even number"
else
  echo "$n is odd number"
fi

addition using loop....
n=$1
result=0
j=0

ADD(){
    result=`expr $result + $j`
}

#for (( i=1; i<=$n; i++ ))
for i in {0..$n..1}
do
    ADD
    j=`expr $j + $1`
done

echo $result






…….
#!/bin/bash

num1=1
num2=10
if [ $num1 -gt $num2 ]; then
               echo "number  one is greather  "
else
         echo "number two is greater"
fi


@for comapre  number
...................................
#!/bin/bash

num1=1
num2=10
if [ $num1 -eq $num2 ]; then
               echo "number  is equel  "
else
         echo "not equel"
fi

@for check odd or even number
......................
#!/bin/bash

echo -n "please enter a number"
read n
check=$(($n % 2))
if [ $check -eq 0 ];then
echo "$n is an even number"
else
echo "$n is an odd number"
fi;
-------------------------------
@for string comparisom


#!/bin/bash

num1="jahid"
num2="arif"
if [ $num1 = $num2 ]; then
               echo "name is equal  "
else
         echo "not equal"
fi
-----------------------
@FOR counting

#!/bin/bash

COUNT=6
while [ $COUNT -gt 0 ]; do
echo value of count is: $COUNT
let COUNT=COUNT-1
done
----------------
@ for reverse
#!/bin/bash

COUNT=1
while [ $COUNT -lt 7 ]; do
echo value of count is: $COUNT
let COUNT=COUNT+1
done

-----------------------
#!/bin/bash

COUNT=0
until [ $COUNT -gt 5 ]; do
echo value of count is: $COUNT
let COUNT=COUNT+1
done
@ addition

echo '#### let ###'
let addition=3+5
echo "3+5 =" $addition

@subtraction

echo '#### let ###'
let subtraction=5-3
echo $subtraction


@power of
echo '#### let ###'
let poweroftwo=2**2
echo "2^ 2=" $poweroftwo

@mathmatatics

echo 2^8 =$[ 2** 8 ]