>perl -E"open my $fh,'<','nonexistent'; say 0+$^E; say ''.$^E;"
2
The system cannot find the file specified
就像$!,$^ E是一个双变量,一个包含两个值的标量.一个是字符串,一个是数字.
>perl -E"say $^E = 0x20;"
The process cannot access the file because it is being used by another process