Perl Programming/Keywords/-z
The -z keyword
edit-z is a file test that returns true, if the file has zero size (is empty).
It takes one argument, either a FILENAME, a FILEHANDLE, or a DIRHANDLE to test the associated file to see if the file has zero size. If the argument is omitted, it tests $_. -z returns 1 for true and an empty string for false. If the file doesn't exist or can't be examined, it returns undef and sets $! (errno).
Syntax
edit -z FILENAME
-z FILEHANDLE
-z EXPRESSION
-z DIRHANDLE
-z