To copy the permissions from one file to another file on Linux, you can use the chmod command with the --reference option. Here is an example of how to do this:
chmod --reference=source.txt destination.txt
This command will set the permissions of the file destination.txt to be the same as those of the file source.txt.
You can also use the chown command with the --reference option to copy the ownership of a file to another file. For example:
chown --reference=source.txt destination.txt
This command will set the owner and group of the file destination.txt to be the same as those of the file source.txt.
Note that these commands will only copy the permissions and ownership of a file, and not other metadata such as the timestamps. If you want to preserve all metadata, you can use the cp command with the -a option. For example:
cp -a source.txt destination.txt
This command will copy the file source.txt to destination.txt, preserving all metadata.