Changing permissions

[Greg Booth]

On Saturday 21 July 2007 11:19:10 am Nigel Ridley wrote:
> D. Michael McIntyre wrote:
> > On Saturday 21 July 2007, Dotan Cohen wrote:
> >> You don't want to format that thing ext2/3. It won't be useable in
> >> WindBlows anymore, and thus the portability of the device is rather
> >> compromised. I suppose that you could tar files that you must keep
> >> permissions for.
> >
> > You can do it if you never intend to use the stick with anything that
> > isn't Linux though.  I expect.  I haven't actually done it, but I used to
> > format floppies for Linux.  It should work.
> >
> >> Note that I think that it is unusual that the execute bit would be set
> >> on files from an insecure device such as a USB stick. I haven't
> >> checked what this machine, does, though. Can someone verify their
> >> machine's behaviour?
> >
> > The execute bit is set on *everything* by default, because there are no
> > permissions in VFAT, and in order for the directories to be readable,
> > they have to be executable.  Since there isn't any way to have
> > fine-grained control without per-file permissions (you have to set up
> > *one* set of fake permissions that are used for everything on the mounted
> > VFAT filesystem) there isn't really a good way around this problem. 
> > That's why the default is usually to use 777 on everything.
> >
> > If you've copied something from a VFAT source that's a 777 (rwxrwxrwx)
> > mess, you can probably fix it with something like this ($directory is the
> > path to whatever directory in question, like
> > /home/foo/junk_I_copied_from_Winderz or whatever):
> >
> >     find $directory -type f|xargs chmod 640
> >     find $directory -type d|xargs chmod 750
> >
> > (Or use 644 and 755.  I keep more restrictive permissions than are the
> > default on most Linux systems.)
> >
> > That will find all the files, then all the directories, respectively, and
> > reassign more appropriate permissions to them.  That's probably
> > sufficient for most situations, I think, though I didn't actually set up
> > a test scenario and play with any of this for real.  I could be spouting
> > nonsense about this 777 thing, since it looks like none of the pictures
> > I've copied off of my memory cards have weird permissions.  Oh well, if I
> > go on record babbling a torrent of bullshit because I think I'm such an
> > all-knowing genius that I don't have to bother fact checking before
> > writing a treatise on a particular subject, then it won't be the first
> > time.  At least I'm honest with myself, eh?  :D
>
> Your pretty much a genius - except you should have done your test first as
> there was a typo:
> find $directory -type f|xargs chmod 640
> find $directory -type d|xargs chmod 750
>
> Needed to remove the '$' before the 'directory'
> But after I removed the offending '$' it worked very well :-) Thank you
>
> Blessings,
>
> Nigel

#1: Easiest way to copy things to and from a USB drive and retain permissions 
is making a tarball !  (  tar -cf [file list]  or something like that )

#2 I don't do it, but I've heard some people keeping a small windows partition 
on a USB drive with the rest ext3, then keeping the windows ext3 drivers on 
the windows side of the usb drive ( http://www.fs-driver.org/ )

Greg