File permissions on Linux file readable but not copyable

[balebel]

Hi Everybody,
I want to make a file readable but not copyable by others in Liunx using chmod, but, I could not do that because the read right automatically make the file copyable.
Please help me, I am in a serious problem

[hans51]

to the best of my knowledge there is no such permission as you like in Linux
whatever you read is already copied - either in a browser or console or by another SW that reads a file
whatever is read thus is copied and hence also can be saved by the read process.

You may have to explain in very details what exactly you need to achieve with your access restriction, then may be there might be a solution to be found or created

[allwimb]

There's no such permission I've already searched for it but as it's said in the previous post every readable thing is copiable.

[jayd512]

Even if you found a way to prevent others from using the cp command or using 'copy and paste' from something like gedit, what would stop them from just getting a screenshot of it?

The only real way to stop someone from copying a file is to restrict their access to it.

[Jonathan183]

I'm guessing you are after something like read only for a pdf or an email (unable to copy/forward etc) ... I think these will depend on applications able to read the information complying with rules ... rather than file permissions

[Cabhan]

If a file is readable, it is copyable. Of course. I could always open a file, then by-hand copy it into another file. You cannot prevent someone from copying a file.

If you are referring to something like copy protection in a PDF, this is a flag set in the PDF file format that must be respected by the software. I can physically copy the file, but I may not be able to copy the text if I open it with Adobe Reader. Note that a lot of other PDF software (such as xpdf) does not respect such restrictions, as I recall, so you can still copy the text if you use another program.

In short, certainly with plain text, you cannot do this. If you are using a file format that allows you to set such constraints, and have written the only software that can read it, I suppose you might be able to enforce it, but this is unlikely, and not a great idea in any case.

What is your use case here? Perhaps we can help you with something else.