gandalf@csli.stanford.edu (Juergen Wagner) (12/14/88)
The manual page for chgrp(1) says:
[SunOS 4.0]
chgrp changes the group-ID of the filenames given as argu-
ments to group.
...
-R Recursive. chgrp descends through the directory, and
any subdirectories, setting the specified group-ID as
it proceeds. When symbolic links are encountered,
their group is changed, but they are not traversed.
The manual page for chmod(1) says:
[SunOS 4.0]
Change the permissions (mode) of a file or files. Only the
owner of a file (or the super-user) may change its mode.
...
-R Recursively descend through directory arguments, set-
ting the mode for each file as described above. When
symbolic links are encountered, their mode is not
changed and they are not traversed.
Now, try the following:
peano:work(17). touch x
peano:work(18). ln -s x y
peano:work(19). ls -lg x y
-rw-r--r-- 1 wagner parc 0 Dec 2 13:29 x
lrwxrwxrwx 1 wagner parc 1 Dec 2 13:29 y -> x
peano:work(20). chgrp kmem y
peano:work(21). chmod 770 y
peano:work(22). ls -lg x y
-rwxrwx--- 1 wagner parc 0 Dec 2 13:29 x
lrwxrwxrwx 1 wagner kmem 1 Dec 2 13:29 y -> x
peano:work(23).
This shows that chmod changes the protection of the file (as it should),
but chgrp changes the group of the link (shouldn't it change the file's
group?).
[[ Well, perhaps it should, but what does that have to do with the -R
option? --wnl ]]
Juergen Wagner gandalf@csli.stanford.edu
wagner@arisia.xerox.comguy@uunet.uu.net (Guy Harris) (12/30/88)
>This shows that chmod changes the protection of the file (as it should), >but chgrp changes the group of the link (shouldn't it change the file's >group?). This dates back to 4.2BSD. The "chmod" system call follows links, but the "chown" system call doesn't. I remember hearing various reasons why this was done, but I don't remember them sufficiently well to reconstruct them.