Changing Unix group for files

Question

I have a file that a colleague and I are editing together, on a Unix system. We are using Unix group permissions to edit it. We have one Unix group that we are both members of. Whenever I save the file, it changes the Unix group to one that he is not a member of. Is there any way to stop it from doing that?

score 12 · Accepted Answer · edited Oct 22 '11 at 12:05

12

Your options are to set the setgid bit (chmod g+s) on the directory to make files created within it match its group ID, or to use the newgrp command to open a shell with the desired group ID before editing the file.

edited Oct 22 '11 at 12:05

Shawn J. Goff

46,081

answered Mar 13 '09 at 14:14

moonshadow

236

1

I'm not sure this is correct. I think what the what he needs is the setgid bit, not to the sticky bit. From Wikipedia: Setting the setgid permission on a directory (chmod g+s) causes new files and subdirectories created within it to inherit its group ID, rather than the primary group ID of the user who created the file. Activating the sticky bit on the directory will only make sure that only the directories' files' owner, the directory's owner or root can modify the directories' files. – Amelio Vazquez-Reina Oct 21 '11 at 23:09

score 3 · Answer 2 · edited Apr 28 '13 at 14:38

3

One option is to switch group using the command newgrp. It may ask for the group password that you may set with gpasswd.

edited Apr 28 '13 at 14:38

Anthon

79,293

answered Mar 13 '09 at 14:24

jassuncao

131

score 2 · Answer 3 · edited May 18 '12 at 10:29

Uno. change your default login group number to be the same between the two people

username:x:500:514::/home/username:/bin/tcsh
# Where 514 is the group id.

Duo: create a new user id , with a password only known by the two people involved. chown the file to be owned by the new userid. Before editing the file in question, suto the new userid.

Trio:.

cp $EDITOR to $HOME; \# in this example pico
chmod g+s $HOME/pico;
chgrp RELEVANTGROUP $HOME/pico;

Quattro:

sudo chgrp RELEVANTGROUP some/path/to/file \# may require root

Cinco: Create a few Google account and edit the thing SIMULTANEOUSLY in Google docs. (it is neat to watch where the other person is typing). Make a point of changing the sharing perms in Google Docs for "anyone with the link"

Hexo: Split the file in two and have each editor only work on half.

score 0 · Answer 4 · edited May 29 '16 at 13:26

0

Take a look at umask on your system.

edited May 29 '16 at 13:26

jimmij

47,140

answered Mar 13 '09 at 14:12

Joe Suarez

117

OK, default dot files set by our sys admins use a umask of 022. What's a good umask for "don't change it!"? – Mar 13 '09 at 14:22
3

umask is for default permissions, not group ID. – moonshadow Mar 13 '09 at 14:33

John Eipe · Answer 5 · 2019-12-19T10:46:18.100

-1

Here is a good article about Sticky-Bit and other advanced permission settings: https://notes-from-a-dev.blogspot.com/2011/03/modes-and-permission-sticky-bit.html

edited Dec 19 '19 at 10:46

answered Jun 17 '11 at 04:12

John Eipe

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2
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Changing Unix group for files

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