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Old 08-01-2008, 06:37 PM
"Zhengguo Xu"
 
Default newbie's question on file permission

Greeting all!

Recently I encounted a strange problem (or it maybe very obvious for you guys) while copying files and I'd like to ask a question on file permission in linux.

I have a file, lets say 'biology.ppt' and it has permission as follows and i am the owner and it belongs to group 'root'


-rwx------

i want to change it to group, say, 'test', and give permissions to everyone to read and write and execute, what's wrong when I run the following command?

sudo chgrp test biology.ppt

sudo chmod 777 biology.ppt

nothing happened when i run these commands and i tried them with and without sudo. the file still has the permission -rwx------ and root is still the group.

if it matters, the file is on a usb disk mounted in /media


i also tried to create some file in my home directory and i can change it as i want with the same command.

any help would be greatly appreciated.



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Old 08-01-2008, 06:52 PM
"POWERS, ZACK"
 
Default newbie's question on file permission

Hi,
The reason permissions don't change on your USB stick is because your
USB disk is formatted in a filesystem that does not support POSIX
style file permissions. If its FAT16 or FAT32, which it is most likely
is, it doesn't support any type of file permissions. To solve this
issues you will have to reformat your USB disk to a POSIX compliant
filesystem (NTFS would be the best choice for compatibility with
Windows).


-----Original Message-----
From: ubuntu-users-bounces@lists.ubuntu.com on behalf of Zhengguo Xu
Sent: Fri 8/1/2008 2:37 PM
To: Ubuntu User
Subject: newbie's question on file permission

Greeting all!

Recently I encounted a strange problem (or it maybe very obvious for
you
guys) while copying files and I'd like to ask a question on file
permission
in linux.

I have a file, lets say 'biology.ppt' and it has permission as follows
and i
am the owner and it belongs to group 'root'

-rwx------

i want to change it to group, say, 'test', and give permissions to
everyone
to read and write and execute, what's wrong when I run the following
command?

sudo chgrp test biology.ppt
sudo chmod 777 biology.ppt

nothing happened when i run these commands and i tried them with and
without
sudo. the file still has the permission -rwx------ and root is still
the
group.

if it matters, the file is on a usb disk mounted in /media

i also tried to create some file in my home directory and i can change
it as
i want with the same command.

any help would be greatly appreciated.

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Old 08-01-2008, 06:59 PM
Aart Koelewijn
 
Default newbie's question on file permission

On Fri, 01 Aug 2008 20:37:41 +0200, Zhengguo Xu wrote:

> Greeting all!
>
> Recently I encounted a strange problem (or it maybe very obvious for you
> guys) while copying files and I'd like to ask a question on file
> permission in linux.
>
> I have a file, lets say 'biology.ppt' and it has permission as follows
> and i am the owner and it belongs to group 'root'
>
> -rwx------
>
> i want to change it to group, say, 'test', and give permissions to
> everyone to read and write and execute, what's wrong when I run the
> following command?
>
> sudo chgrp test biology.ppt
> sudo chmod 777 biology.ppt
>
> nothing happened when i run these commands and i tried them with and
> without sudo. the file still has the permission -rwx------ and root is
> still the group.
>
> if it matters, the file is on a usb disk mounted in /media
>
> i also tried to create some file in my home directory and i can change
> it as i want with the same command.
>

I have no experiences with usb disks, but in this case I suppose the usb
disk will have I filesystem that does not support owner.group settings of
files. I suppose the ownership and permissions of biology.ppt will be
those of the whole disk and can only be changed for the whole disk, not
for separate files on it.

Aart


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Old 08-01-2008, 07:00 PM
Ansgar Burchardt
 
Default newbie's question on file permission

Hi,

"Zhengguo Xu" <tworiversfolk@gmail.com> writes:

> sudo chgrp test biology.ppt
> sudo chmod 777 biology.ppt
>
> nothing happened when i run these commands and i tried them with and without
> sudo. the file still has the permission -rwx------ and root is still
> the group.
>
> if it matters, the file is on a usb disk mounted in /media

Not all file systems support storing ownership information and
permissions. What file system are you using on the USB disk [1]?

USB disks are often used together with FAT32 which does not support
permissions. Linux then uses permissions based on flags passed to the
mount command.

Regards,
Ansgar

[1] Running `mount' lists all (mounted) file systems and their type

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Old 08-01-2008, 07:07 PM
"Zhengguo Xu"
 
Default newbie's question on file permission

Thanks a lot, Zack!! it indeed is FAT32 disk. I do need to connect this disk to windows from time to time, but I had the impression that NTFs is not best support by Linx. or am I completely wrong about it? writing to NTFs disk in linux is now perfectly normal?



2008/8/1 POWERS, ZACK <zpowers@umflint.edu>

Hi,

The reason permissions don't change on your USB stick is because your

USB disk is formatted in a filesystem that does not support POSIX

style file permissions. If its FAT16 or FAT32, which it is most likely

is, it doesn't support any type of file permissions. To solve this

issues you will have to reformat your USB disk to a POSIX compliant

filesystem (NTFS would be the best choice for compatibility with

Windows).





-----Original Message-----

From: ubuntu-users-bounces@lists.ubuntu.com on behalf of Zhengguo Xu

Sent: Fri 8/1/2008 2:37 PM

To: Ubuntu User

Subject: newbie's question on file permission



Greeting all!



Recently I encounted a strange problem (or it maybe very obvious for

you

guys) while copying files and I'd like to ask a question on file

permission

in linux.



I have a file, lets say 'biology.ppt' and it has permission as follows

and i

am the owner and it belongs to group 'root'



-rwx------



i want to change it to group, say, 'test', and give permissions to

everyone

to read and write and execute, what's wrong when I run the following

command?



sudo chgrp test biology.ppt

sudo chmod 777 biology.ppt



nothing happened when i run these commands and i tried them with and

without

sudo. the file still has the permission -rwx------ and root is still

the

group.



if it matters, the file is on a usb disk mounted in /media



i also tried to create some file in my home directory and i can change

it as

i want with the same command.



any help would be greatly appreciated.




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ubuntu-users@lists.ubuntu.com

Modify settings or unsubscribe at: https://lists.ubuntu.com/mailman/listinfo/ubuntu-users




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Old 08-01-2008, 07:07 PM
Nils Kassube
 
Default newbie's question on file permission

Zhengguo Xu wrote:
> I have a file, lets say 'biology.ppt' and it has permission as follows
> and i am the owner and it belongs to group 'root'
>
> -rwx------
>
> i want to change it to group, say, 'test', and give permissions to
> everyone to read and write and execute, what's wrong when I run the
> following command?
>
> sudo chgrp test biology.ppt
> sudo chmod 777 biology.ppt
>
> nothing happened when i run these commands and i tried them with and
> without sudo. the file still has the permission -rwx------ and root is
> still the group.
>
> if it matters, the file is on a usb disk mounted in /media

Yes, it matters if the file system is FAT32 or NTFS which is the usual
file system for USB disks. FAT32 or NTFS don't know about Unix
permissions and therefore you can't change them.


Nils

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Old 08-01-2008, 07:09 PM
"Zhengguo Xu"
 
Default newbie's question on file permission

many thanks!* all of you. how can I change the permission for whole disk?

2008/8/1 Zhengguo Xu <tworiversfolk@gmail.com>

Thanks a lot, Zack!! it indeed is FAT32 disk. I do need to connect this disk to windows from time to time, but I had the impression that NTFs is not best support by Linx. or am I completely wrong about it? writing to NTFs disk in linux is now perfectly normal?




2008/8/1 POWERS, ZACK <zpowers@umflint.edu>


Hi,

The reason permissions don't change on your USB stick is because your

USB disk is formatted in a filesystem that does not support POSIX

style file permissions. If its FAT16 or FAT32, which it is most likely

is, it doesn't support any type of file permissions. To solve this

issues you will have to reformat your USB disk to a POSIX compliant

filesystem (NTFS would be the best choice for compatibility with

Windows).





-----Original Message-----

From: ubuntu-users-bounces@lists.ubuntu.com on behalf of Zhengguo Xu

Sent: Fri 8/1/2008 2:37 PM

To: Ubuntu User

Subject: newbie's question on file permission



Greeting all!



Recently I encounted a strange problem (or it maybe very obvious for

you

guys) while copying files and I'd like to ask a question on file

permission

in linux.



I have a file, lets say 'biology.ppt' and it has permission as follows

and i

am the owner and it belongs to group 'root'



-rwx------



i want to change it to group, say, 'test', and give permissions to

everyone

to read and write and execute, what's wrong when I run the following

command?



sudo chgrp test biology.ppt

sudo chmod 777 biology.ppt



nothing happened when i run these commands and i tried them with and

without

sudo. the file still has the permission -rwx------ and root is still

the

group.



if it matters, the file is on a usb disk mounted in /media



i also tried to create some file in my home directory and i can change

it as

i want with the same command.



any help would be greatly appreciated.




--

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ubuntu-users@lists.ubuntu.com

Modify settings or unsubscribe at: https://lists.ubuntu.com/mailman/listinfo/ubuntu-users






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Old 08-01-2008, 07:12 PM
"Zhengguo Xu"
 
Default newbie's question on file permission

mount output:

...
/dev/sdb5 on /media/disk type vfat (rw,nosuid,nodev,uhelper=hal,shortname=mixed,uid=1 000,utf8,umask=077,flush)
/dev/sdc5 on /media/disk-1 type vfat (rw,nosuid,nodev,uhelper=hal,shortname=mixed,uid=1 000,utf8,umask=077,flush)


i'm not gonna pretend to understand that. :-(
i want the disk can be read by different users on my pc. all of them should be able to write/delete some files on it. is it doable?


2008/8/1 Zhengguo Xu <tworiversfolk@gmail.com>

many thanks!* all of you. how can I change the permission for whole disk?

2008/8/1 Zhengguo Xu <tworiversfolk@gmail.com>


Thanks a lot, Zack!! it indeed is FAT32 disk. I do need to connect this disk to windows from time to time, but I had the impression that NTFs is not best support by Linx. or am I completely wrong about it? writing to NTFs disk in linux is now perfectly normal?





2008/8/1 POWERS, ZACK <zpowers@umflint.edu>



Hi,

The reason permissions don't change on your USB stick is because your

USB disk is formatted in a filesystem that does not support POSIX

style file permissions. If its FAT16 or FAT32, which it is most likely

is, it doesn't support any type of file permissions. To solve this

issues you will have to reformat your USB disk to a POSIX compliant

filesystem (NTFS would be the best choice for compatibility with

Windows).





-----Original Message-----

From: ubuntu-users-bounces@lists.ubuntu.com on behalf of Zhengguo Xu

Sent: Fri 8/1/2008 2:37 PM

To: Ubuntu User

Subject: newbie's question on file permission



Greeting all!



Recently I encounted a strange problem (or it maybe very obvious for

you

guys) while copying files and I'd like to ask a question on file

permission

in linux.



I have a file, lets say 'biology.ppt' and it has permission as follows

and i

am the owner and it belongs to group 'root'



-rwx------



i want to change it to group, say, 'test', and give permissions to

everyone

to read and write and execute, what's wrong when I run the following

command?



sudo chgrp test biology.ppt

sudo chmod 777 biology.ppt



nothing happened when i run these commands and i tried them with and

without

sudo. the file still has the permission -rwx------ and root is still

the

group.



if it matters, the file is on a usb disk mounted in /media



i also tried to create some file in my home directory and i can change

it as

i want with the same command.



any help would be greatly appreciated.




--

ubuntu-users mailing list

ubuntu-users@lists.ubuntu.com

Modify settings or unsubscribe at: https://lists.ubuntu.com/mailman/listinfo/ubuntu-users








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Old 08-01-2008, 07:17 PM
"POWERS, ZACK"
 
Default newbie's question on file permission

Both read and write permissions are supported with NTFS in Linux
through the FUSE module. In Ubuntu this support can be installed by
using Synaptic to install the ntfs-3g package. Since 7.04 Feisty Fawn,
ntfs-3g has been the default for mounting NTFS partitions. Once you
mount the volume with ntfs-3g then you may use POSIX styled file
permissions on all files.
-----Original Message-----
From: ubuntu-users-bounces@lists.ubuntu.com on behalf of Zhengguo Xu
Sent: Fri 8/1/2008 3:09 PM
To: Ubuntu user technical support,not for general discussions
Subject: Re: newbie's question on file permission

many thanks! all of you. how can I change the permission for whole
disk?

2008/8/1 Zhengguo Xu <tworiversfolk@gmail.com>

> Thanks a lot, Zack!! it indeed is FAT32 disk. I do need to connect
this
> disk to windows from time to time, but I had the impression that
NTFs is not
> best support by Linx. or am I completely wrong about it? writing to
NTFs
> disk in linux is now perfectly normal?
>
>
> 2008/8/1 POWERS, ZACK <zpowers@umflint.edu>
>
>> Hi,
>> The reason permissions don't change on your USB stick is because
your
>> USB disk is formatted in a filesystem that does not support POSIX
>> style file permissions. If its FAT16 or FAT32, which it is most
likely
>> is, it doesn't support any type of file permissions. To solve this
>> issues you will have to reformat your USB disk to a POSIX compliant
>> filesystem (NTFS would be the best choice for compatibility with
>> Windows).
>>
>>
>> -----Original Message-----
>> From: ubuntu-users-bounces@lists.ubuntu.com on behalf of Zhengguo
Xu
>> Sent: Fri 8/1/2008 2:37 PM
>> To: Ubuntu User
>> Subject: newbie's question on file permission
>>
>> Greeting all!
>>
>> Recently I encounted a strange problem (or it maybe very obvious
for
>> you
>> guys) while copying files and I'd like to ask a question on file
>> permission
>> in linux.
>>
>> I have a file, lets say 'biology.ppt' and it has permission as
follows
>> and i
>> am the owner and it belongs to group 'root'
>>
>> -rwx------
>>
>> i want to change it to group, say, 'test', and give permissions to
>> everyone
>> to read and write and execute, what's wrong when I run the
following
>> command?
>>
>> sudo chgrp test biology.ppt
>> sudo chmod 777 biology.ppt
>>
>> nothing happened when i run these commands and i tried them with
and
>> without
>> sudo. the file still has the permission -rwx------ and root is
still
>> the
>> group.
>>
>> if it matters, the file is on a usb disk mounted in /media
>>
>> i also tried to create some file in my home directory and i can
change
>> it as
>> i want with the same command.
>>
>> any help would be greatly appreciated.
>>
>>
>> --
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>> ubuntu-users@lists.ubuntu.com
>> Modify settings or unsubscribe at:
>> https://lists.ubuntu.com/mailman/listinfo/ubuntu-users
>>
>>
>

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Old 08-01-2008, 07:22 PM
Florian Diesch
 
Default newbie's question on file permission

"Zhengguo Xu" <tworiversfolk@gmail.com> wrote:

> Recently I encounted a strange problem (or it maybe very obvious for you
> guys) while copying files and I'd like to ask a question on file permission
> in linux.
>
> I have a file, lets say 'biology.ppt' and it has permission as follows and i
> am the owner and it belongs to group 'root'
>
> -rwx------
>
> i want to change it to group, say, 'test', and give permissions to everyone
> to read and write and execute, what's wrong when I run the following
> command?
>
> sudo chgrp test biology.ppt
> sudo chmod 777 biology.ppt
>
> nothing happened when i run these commands and i tried them with and without
> sudo. the file still has the permission -rwx------ and root is still the
> group.
>
> if it matters, the file is on a usb disk mounted in /media

That matters. most likely it is on a file system, that doesn't
support unix file permissions (like FAT). Then file permissions are
emulated and set at mount time using mount options like uid, gid,...
(see man mount for more about this). AFAIK there'no simple way to
change the permissions for automounted file systems, but you may
unmount and mount the filesystem manually.



Florian
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