Introduction

You may know how to change file permissions using chmod but, if you already have a file with the permissions you want to assign to some other files, you can use --reference option in chmod

How to copy or replicate file permissions, using another file as reference

If you want to use a file as reference to copy its permissions to other files you can do that using this command

chmod --reference <reference-file> <target-file>

As an example, if you have this:

-rwxrwxrwx 1 ggarron ggarron 0 Dec 20 15:35 1.txt
-rwx------ 1 ggarron ggarron 0 Dec 20 15:35 2.txt

And you run:

chmod --reference 1.txt 2.txt

You should then have this:

-rwxrwxrwx 1 ggarron ggarron 0 Dec 20 15:35 1.txt
-rwxrwxrwx 1 ggarron ggarron 0 Dec 20 15:35 2.txt

Just be sure, you are the owner of the files, you that you have permission to change them.