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blogin4:~ $ chgrp prj00012 somefile.txt
blogin4:~ $ ls -l somefile.txt
-rw-------  1 myaccount prj00012 237271040 Jul  3  2020 somefile.txt

To change all small number of files in a directory recusively, use "chgrp -R".  To update lots of files, especially on the Lustre filesystems, you should use "lfs find" instead:

blogin4:~ $ lfs find somedirectory | xargs chgrp prj00012 
blogin4:~ $ ls -ld somedirectory
drwx------  1 myaccount  prj00012      4096 Jul  3  2020 somedirectory

If your file or directory names contain spaces, you will need to use "lfs find -0 ... | xargs -0 ..." instead.

Access for group members

Once a file (or a complete directory) has the group ownership, the file might be accessed by all users in the group.

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