Perl -X Function


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Syntax

-X FILEHANDLE
-X

Definition and Usage

A file test, where X is one of the letters listed below. his unary operator takes one argument, either a filename or a filehandle, and tests the associated file to see if something is true about it.

If the argument is omitted, tests $_

Return Value

  • 1 if condition is true
  • 0 if condition is false
-r	File is readable by effective uid/gid.
-w	File is writable by effective uid/gid.
-x	File is executable by effective uid/gid.
-o	File is owned by effective uid.

-R	File 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.

-e	File exists.
-z	File has zero size (is empty).
-s	File has nonzero size (returns size in bytes).

-f	File is a plain file.
-d	File is a directory.
-l	File is a symbolic link.
-p	File is a named pipe (FIFO), or Filehandle is a pipe.
-S	File is a socket.
-b	File is a block special file.
-c	File is a character special file.
-t	Filehandle is opened to a tty.

-u	File has setuid bit set.
-g	File has setgid bit set.
-k	File has sticky bit set.

-T	File is an ASCII text file (heuristic guess).
-B	File is a "binary" file (opposite of -T).

-M	Script start time minus file modification time, in days.
-A	Same for access time.
-C	Same for inode change time

Example

Try out following example with some file.

stat($filename);
print "Readable\n" if -r _;
print "Writable\n" if -w _;
print "Executable\n" if -x _;
print "Setuid\n" if -u _;
print "Setgid\n" if -g _;
print "Sticky\n" if -k _;
print "Text\n" if -T _;
print "Binary\n" if -B _;

# Another way of testing
if( -e $filename ){
   print " File $filename exists\n";
}

perl_function_references.htm

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