Or in Perl and | | The difference between _perl

Let's see what the following code will output?

Copy Code code as follows:

My $a = 0;
$a = $a or 1;
Print $a, "\ n";
$a = $a | | 1;
Print $a, "\ n";

Output:
0
1
Why, then? because | |, =, or these three priorities are gradually lowered from left to right.
So, you can write this:
Chomp (My $filename = Shift (@ARGV) | | <STDIN>);

This will not work:
Chomp (My $filename = Shift (@ARGV) or <STDIN>);
You will be prompted with the following error:
Can ' t modify Logical OR (| |) in CHOMP