-e File or directory exists.
-z File is empty (zero size).
-s File is not empty; function returns size in bytes.
-f Argument is a plain file.
-d Argument is a directory.
-l Argument is a symbolic link.
-p Argument is a named pipe.
-S Argument is a socket.
-b File is a block special file.
-c File is a character special file.
-t Filehandle is an open tty (isatty()).
-f Argument is readable by effective uid/gid.
-w Argument is writable by effective uid/gid.
-x Argument is executable by effective uid/gid.
-o Argument is owned by effective uid.
-R Argument is readable by real uid/gid.
-W File is writable by real uid/gid.
-X File is executable by real uid/gid.
-O File is owned by real uid.
-T File is an ASCII text file.
-B File is a binary file.
-u Argument has setuid bit set.
-g Argument has setgid bit set.
-k Argument has sticky bit set.
-M Time in days from argument modification time to Perl program start time.
-A Time in days from argument access time to Perl program start time.
-C Time in days from argument change time to Perl program start time.