I'm doing a bash shell script and I want to change the default group that new files are created as. I know you use
umask to change the permissions. Is there something for the group?
newgrpcommand is used to change the current group ID during a login session.
New directories created in that session will have the group ID set by the command.
There are a couple ways to do this:
You can change the default group for all files created in a particular
directory by setting the setgid flag on the directory (
chmod g+s _dir_).
New files in the directory will then be created with the group of the
directory (set using
chgrp <group> <dir>). This applies to any program
that creates files in the directory.
Note that this is automagically inherited for new subdirectories (as of
Linux 3.10), however, if sub-directories were already present, this change
won't be applied to them (use the
-R flag for that).
If the setgid flag is not set, then the default group will be set to the current
group id of the creating process. Although this can be set using the
command, that creates a new shell that is difficult to use within a shell
script. If you want to execute a particular command (or set of commands)
with the changed group, use the command
sg <group> <command>.
sg is not a POSIX standard command but is available on Linux.