控制 UNIX 目录内容用户组所有权

您可以为 GID 执行此操作：

chgrp users /path/to/directory
chmod g+s /path/to/directory

您不能为 UID 执行此操作。直接地。

您可以编写一个经常运行命令的 cron 条目：

chown -R user:group /path/to/directory
chmod -R 644 /path/to/directory

（确保挂载 /path/to/directory 在 nosuid 上的文件系统，以避免有人将 setuid shell 放入目录的竞争条件）

chown user:group file?

我很抱歉这么说，但请使用 RTFM。来自chmod(1)：

       Modes may be absolute or symbolic.  An absolute mode is an octal number
       constructed from the sum of one or more of the following values:

       4000    (the setuid bit).  Executable files with this bit set will
               run with effective uid set to the uid of the file owner.
               Directories with this bit set will force all files and sub-
               directories created in them to be owned by the directory
               owner and not by the uid of the creating process, if the
               underlying file system supports this feature: see chmod(2)
               and the suiddir option to mount(8).
       2000    (the setgid bit).  Executable files with this bit set will
               run with effective gid set to the gid of the file owner.
       1000    (the sticky bit).  See chmod(2) and sticky(8).
       0400    Allow read by owner.
       0200    Allow write by owner.
       0100    For files, allow execution by owner.  For directories,
               allow the owner to search in the directory.
       0040    Allow read by group members.
       0020    Allow write by group members.
       0010    For files, allow execution by group members.  For directo-
               ries, allow group members to search in the directory.
       0004    Allow read by others.
       0002    Allow write by others.
       0001    For files, allow execution by others.  For directories
               allow others to search in the directory.