while condition one liners

Home

To print values till 10 using while

# COUNTER=0; while [ $COUNTER -lt 10 ]; do

echo The counter is $COUNTER

let COUNTER=COUNTER+1

done

To create an infinite loop using while that exits on CTRL+C key

# while true; do

echo -n "Make your choice: "

read value

echo

echo "You Entered $value "

done

To calculate factorial using while loop:

#!/bin/bash

counter=$1

factorial=1

while [ $counter -gt 0 ]

do

   factorial=$(( $factorial * $counter ))

   counter=$(( $counter - 1 ))

done

echo $factorial

While loops are frequently used for reading data line by line from file:

#!/bin/bash

FILE=$1

# read $FILE using the file descriptors

exec 3<&0

exec 0<$FILE

while read line

do

      # use $line variable to process line

      echo $line

done

exec 0<&3

Conditional while loop with break statement

while [ condition ]

do

   statements1      #Executed as long as condition is true and/or, up to a disaster-condition if any.

   statements2

  if (disaster-condition)

  then

      break                #Abandon the while lopp.

  fi

  statements3          #While good and, no disaster-condition.

done

Back To Top
Home