From: Paul Lutus <nospam@...>
Date: 2006-11-17T14:20:05+09:00
Subject: Re: Changing permission on a file

App Ra wrote:

> I'm trying to change permission on a file on a windows machine. This
> should work according to the documentation (may be i'm missing something
> here). But it doesn't

Be specific. What did you expect, and what did you get instead? Any error
messages?

> here is the code:
> 
>   # take away read permission
>   new_permission = File.lstat("testfile").mode ^ 0004

Hoo-boy. Do you know what "^" actually does? Do it this way:

x & 4 ^ 0xffff

Meaning original value "AND" the bit-flip of the desired pattern. That way,
you actually get a predictable result, regardless of the original value,
instead of an unpredictable toggle.

>   File.chmod(new_permission, "testfile" )
>   File.readable?("testfile")  #=> true
> 
> or
> 
>   new_permission = File.lstat("testfile").mode ^ File::O_R

Again, think about what "^" does, and which input arguments produce which
output arguments.

>   File.chmod(new_permission, "testfile" )
> 
> What am I doing wrong?

Also, be sure to say what happened, how you know something is wrong.

-- 
Paul Lutus
http://www.arachnoid.com