chgrp: operation not permitted even though I own the file!

the theorist · 11-21-2003, 06:59 PM

I want to chgrp a file (from my default user group) to another group of which I'm a member. So:

Code:

$ chgrp <newgroup>  <file that I own> 
chgrp: changing group of '<file that I own>': Operation not permitted

Why can't I change it?
Interstingly, root can change the group, and then the regular user can change it back to the user's default group.

I'm using Red Hat 7.2 on a ext3 file system.

chup · 11-21-2003, 07:04 PM

tried chown?

the theorist · 11-21-2003, 07:14 PM

chup:
Yes; the error occurs if I try:

Code:

chown <same user>:<new group> <file that I own>

on a file that I both own and is in my default user group. Also if I just try to change the user.
(I'm assuming that I can't chown on a file I don't own... so I didn't test that!)

tearinox · 11-21-2003, 07:16 PM

CHOWN SYNTAX = chown [options] user[:group] file...

CHGRP SYNTAX = chgrp [options] group file...

Chown does what chgrp can, plus its older so you know it will work better.
Note, that was right from the manual pages you should be reading =P

tearinox · 11-21-2003, 07:17 PM

type ls -l so we can see the file

darthtux · 11-21-2003, 07:30 PM

To change the group ownership of a file to another group you have to be a member of that group or root. That is why you are getting the Operation not permitted error.

the theorist · 11-21-2003, 07:35 PM

tearinox: That's what I'm doing (with no [options]); I've been over the man pages several times other web pages several times. I'm pretty sure the syntax is right.

Here's an explicit example: (my username is "will" and I want to change to group "ezra")

Code:

[20:30:47][will][0]$ ls -l testfile
-rw-rw-r--    1 will     will           20 Nov 21 20:30 testfile
[20:30:54][will][0]$ chgrp ezra testfile
chgrp: changing group of `testfile': Operation not permitted

the theorist · 11-21-2003, 07:42 PM

darthtux:
I'm a member of the group. This is the last line of /etc/group:

Code:

 ezra:x:504:will,sam

In any case, I can change the group membership of testfile back to "will", after root has changed it to "ezra". So I think the system recognizes I'm in the target group.

I posted in the newbie forum because I figured it was something common but not obvious; I'm not an idiot (most of the time).

darthtux · 11-21-2003, 07:44 PM

What about
chown will.ezra file

the theorist · 11-21-2003, 08:10 PM

darthtux:
Nope, same "operation not permitted result".

Thanks for everyone's comments. I'm starting to think its something uniquely screwy with my RedHat 7.2 installation. (Although, otherwise, I haven't had problems with it.) I'll try it out on another system and report back later.
If anyone has any weird ideas, feel free to tell me!

the theorist · 11-22-2003, 03:24 PM

I found the same results on my RedHat 9.0 system, too. Weird.

the theorist · 11-24-2003, 08:28 AM

Apparently I needed to reboot (on both 7.2 and 9.0) to get the system to fully (?) recognize the new group settings. I added the group "ezra" with groupadd, and then manually edited /etc/group to put user "will" in group "ezra". Rebooting let me change the group permission, as sought above.

Perhaps I should have used "usermod -G ezra will" to do this.

scraimer · 08-22-2006, 02:14 AM

Groups don't update until you log-in again. So even if you edit /etc/groups, you still have to logout and log in again (or just run another shell inside the current one. That should give the same effect :-)

DaveQB · 12-30-2006, 03:20 AM

This had me stumpped too and I have been using Linux for years, both server and desktop.

You do need to login again.

scraimer running 'bash' and then trying to chgrp again doesn't work either, unfortunately.

iggi · 11-27-2007, 09:10 AM

You can also use

Code:

newgrp <group>

to change to the group without a restart/logout (actually changes your primary group to <group>).

What I was wondering: why do you have to be part of the group <target> in order to be able to change the current group ownership to <target>? Some kind of a security mechanism which I'm overlooking?