04. Looping control flow continue, break

In cases of exceptions, where we find that we want to direct the flow of the loop back to the test condition or break out of it, we can use two commands - continue and break.

continue

The continue keyword is used to ignore the rest of the statements for that loop iteration, and go back to the test condition.

This short script breaks forces the loop to go back to the condition when $var is equal to 5. Thus, the output would print out all values up to 10 except 5.

#!/bin/bash
 
for var in {1..10}
do
  if [ $var -eq 5 ]
  then
    continue;
  fi
  echo "$var"
done
$ ./test
1
2
3
4
6
7
8
9
10

break

To break out of a loop, simply use the command break.

If there is more than one loop you want break out of, you can specify a value after the keyword.

#!/bin/bash
 
for iter in {2..4}
do
  for var in {1..10}
  do
    if [ $var -eq 5 ]
    then
      break 2;
    fi
    echo $(($iter * $var))
  done
done

This script would print out 2 4 6 8 and then break out of both loops. Can you see why?

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