While Loop

 Implementation of `While` Loop in Shell Script.

vim looping.sh

chmod +x looping.sh  (./looping.sh)

====================================

#/bin/bash

a=0

# lt is less than operator

#Iterate the loop until a less than 10

while [ $a -lt 10 ]

do

# Print the values

echo $a

# increment the value

a=`expr $a + 1`

done

=============================

#/bin/bash

a=0

# -gt is greater than operator

#Iterate the loop until a is greater than 10

until [ $a -gt 10 ]

do

# Print the values

echo $a

# increment the value

a=`expr $a + 1`

done

==================

Implementation of `for` Loop with `break` statement in Shell Script.

#/bin/bash

#Start of for loop

for a in 1 2 3 4 5 6 7 8 9 10

do

# if a is equal to 5 break the loop

if [ $a == 5 ]

then

break

fi

# Print the value

echo “Iteration no $a”

done

==================

Implementation of `for` Loop with `continue` statement in Shell Script.

#/bin/bash

for a in 1 2 3 4 5 6 7 8 9 10

do

# if a = 5 then continue the loop and

# don’t move to line 8

if [ $a == 5 ]

then

continue

fi

echo “Iteration no $a”

done

====================

Implementing `until` Loop in Shell Script

#/bin/bash

a=0

# -gt is greater than operator

#Iterate the loop until a is greater than 10

until [ $a -gt 10 ]

do

=======================

Creating an Infinite Loop with “while true” in Shell Script

#/bin/bash

while true

do

# Command to be executed

# sleep 1 indicates it sleeps for 1 sec

echo “Hi, I am infinity loop”

sleep 1

done