Block binding in Perl refers to how variables are scoped within a particular code block. The my keyword can be used to declare a variable with block scope.
For example:
{
my $x = 5; # $x is only visible within this block
print $x; # prints 5
}
print $x; # throws an error because $x is not defined in this scope
Another example:
my $x = 10;
{
my $x = 5; # this $x is a different variable from the previous $x
print $x; # prints 5
}
print $x; # prints 10
In the above example, the first $x is defined outside the block, while the second $x is defined within the block. The first $x is visible outside of the block, while the second $x is only visible within the block.