There may be times when you'll want all files that get created in a shared directory to have the same access control list. We can do that by applying an inherited ACL to the directory. Although, understand that, even though this sounds like a cool idea, creating files in the normal way will cause files to have the read/write permissions set for the group, and the read permission set for others. So, if you're setting this up for a directory where users just create files normally, the best that you can hope to do is to create an ACL that adds either the write or execute permissions for someone. Either that, or ensure that users set the 600 permissions settings on all files that they create, assuming that users really do need to restrict access to their files.
On the other hand, if you're creating a shell script that creates files in a specific directory, you can include chmod commands to ensure that the files get created with the restrictive permissions that are necessary to make your ACL work as intended.
To demo, let's create the new_perm_dir directory, and set the inherited ACL on it. I want to have read/write access for files that my shell script creates in this directory, and for Frank to have only read access. I don't want anyone else to be able to read any of these files:
[donnie@localhost ~]$ setfacl -m d:u:frank:r new_perm_dir
[donnie@localhost ~]$ ls -ld new_perm_dir
drwxrwxr-x+ 2 donnie donnie 26 Nov 12 13:16 new_perm_dir
[donnie@localhost ~]$ getfacl new_perm_dir
# file: new_perm_dir
# owner: donnie
# group: donnie
user::rwx
group::rwx
other::r-x
default:user::rwx
default:user:frank:r--
default:group::rwx
default:mask::rwx
default:other::r-x
[donnie@localhost ~]$
All I had to do to make this an inherited ACL was to add the d: before the u:frank. I left the default permissions settings on the directory, which allows everyone read access to the directory. Next, I'll create the donnie_script.sh shell script that will create a file within that directory, and that will set read/write permissions for only the user of the new files:
#!/bin/bash
cd new_perm_dir
touch new_file.txt
chmod 600 new_file.txt
exit
After making the script executable, I'll run it and view the results:
[donnie@localhost ~]$ ./donnie_script.sh
[donnie@localhost ~]$ cd new_perm_dir
[donnie@localhost new_perm_dir]$ ls -l
total 0
-rw-------+ 1 donnie donnie 0 Nov 12 13:16 new_file.txt
[donnie@localhost new_perm_dir]$ getfacl new_file.txt
# file: new_file.txt
# owner: donnie
# group: donnie
user::rw-
user:frank:r-- #effective:---
group::rwx #effective:---
mask::---
other::---
[donnie@localhost new_perm_dir]$
So, new_file.txt got created with the correct permissions settings, and with an ACL that allows Frank to read it. (I know that this is a really simplified example, but you get the idea.)