Perl Programming/Keywords/-u

The -u keyword

-u is a file test that tests if the file has the setuid bit set.

It takes one argument, either a FILENAME, a FILEHANDLE, or a DIRHANDLE to test the associated file to see, if something is true about it. If the argument is omitted, it tests $_. -u 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

  -u FILENAME
  -u FILEHANDLE
  -u EXPRESSION
  -u DIRHANDLE
  -u