In the previous section, we discussed about how continue can be used to exit from the current iteration of a loop. The break command is another way to introduce a new condition within a loop. Unlike continue, however, it causes the loop to be terminated altogether if the condition is met.

In the for_12.sh script, we check the directory's content. If the directory is found, then we are exiting the loop and displaying the message that the first directory is found:

#!/bin/bash
rm -rf sample*
echo > sample_1
echo > sample_2
mkdir sample_3
echo > sample_4

for file in sample*
do
  if [ -d "$file" ]; then
    break;
  fi
done

echo The first directory is $file
rm -rf sample*
exit 0

Let's test the program:

$ chmod +x for_12.sh
$ ./for_12.sh

The following will be the output after executing the preceding commands:

The first directory is sample_3

In the for_13.sh script, we ask the user to enter any number. We print the square of numbers in the while loop. If a user enters the number 0, then we use the break command to exit the loop:

#!/bin/bash
typeset -i  num=0
while true
do
  echo -n "Enter any number (0 to exit): "
  read num junk

  if (( num == 0 ))
  then
    break
  else
    echo "Square of $num is $(( num * num ))."
  fi
done

echo "script has ended"

Let's test the program:

$ chmod +x for_13.sh
$ ./for_13.sh

The following will be the output after executing the preceding commands:

Enter any number (0 to exit): 1
Square of 1 is 1.
Enter any number (0 to exit): 5
Square of 5 is 25.
Enter any number (0 to exit): 0