Linux Shell Script for Loops

 Loops are repeated set of actions for a range of values.

For loop

Below are some Examples

echo "Fix values in for loop"

for i in 1 2 3 4 5

do

        echo $i

done

echo "Range values"

for i in {1..10}

do

        echo $i

done

echo "Step values with Range"

for i in {0..10..2}

do

        echo $i

done

echo "c style for loop"

for (( c=1; c<=5; c++ ))

do

        echo $c

done

echo "break statement example which exit from the loop whenever break statement is encountered"

for i in {1..10}

do

    if [ $i -eq 5 ]

    then

      break

    fi

        echo $i

done

echo "continue statement to continue the loop"

for i in {1..10}

do

    var1=`expr $i % 2`

    if [ $var1 -eq 0 ]

    then

      continue

    fi

        echo $i

done

echo "Looping with array"

Zones=('zone1' 'zone2' 'zone3')

for i in "${Zones[@]}"

do

        echo $i

done

Execute

./loop.sh

Output

Fix values in for loop

1

2

3

4

5

Range values

1

2

3

4

5

6

7

8

9

10

Step values with Range

0

2

4

6

8

10

c style for loop

1

2

3

4

5

break statement example which exit from the loop whenever break statement is encountered

1

2

3

4

continue statement to continue the loop

1

3

5

7

9

Looping with array

zone1

zone2

zone3

While loop

It repeats the set of statements on the basis of conditions which are supplied with the while loop

choice="Y"

while [ $choice == "Y" ]

do

        echo "Enter the choice(Y/N)"

        read choice

done

echo "Program ends here"

Execute

./loop.sh