From: Robert Klemme <shortcutter@...>
Date: 2012-02-08T07:20:08+09:00
Subject: Re: Make a file read-only?

On Mon, Feb 6, 2012 at 9:14 PM, Jeremy Bopp <jeremy@bopp.net> wrote:
> On 02/06/2012 01:38 PM, Intransition wrote:
> More specifically, then, you want to remove the write permission from
> the file, leaving it whatever other permissions were already set
> (possibly none!).  In other words, you want to /mask out/ the write bits
> from whatever the current file mode is.  Try the following:
>
> mode = 0100664
> mask = mode ^ 0222
> new_mode = mode & mask

Interesting approach.  I usually do it like this:

irb(main):038:0> mode = 0100664
=> 33204
irb(main):039:0> mask = 0222
=> 146
irb(main):040:0> new_mode = (mode | mask) ^ mask
=> 33060
irb(main):041:0> "%07o" % new_mode
=> "0100444"

Kind regards

robert

-- 
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