In Perl, unless is a conditional statement that allows you to execute a piece of code if a certain condition is false. The syntax for using unless is:
unless (condition) {
# Code to execute if the condition is false
}
Here's an example:
my $num = 10;
unless ($num % 2 == 0) {
print "$num is not even";
}
In this example, unless checks if $num is even. If it's not, it executes the code inside the block and prints the message "10 is not even".
You can also use else with unless to execute a different block of code when the condition is true. Here's an example:
my $num = 10;
unless ($num % 2 == 0) {
print "$num is not even";
} else {
print "$num is even";
}
In this example, unless checks if $num is even. Since it is, it executes the code inside the else block and prints the message "10 is even".