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Answer 1

+2 A:

It looks like the following in .screenrc does the trick:

escape ''

This does not set the escape character to ', but disables the escape mechanism entirely.

Greg Hewgill 2009-02-02 00:53:52

I successfully managed to get into screen's command mode (or whatever) by typing Ctrl-Shift-@ (which outputs 0x00 to the terminal) using your example.

strager 2009-02-02 01:08:12

Hmm, I tried that keystroke too but was unable to make that work. That's why I said I wouldn't count on it. :)

Greg Hewgill 2009-02-02 01:11:36

Your update works (or, at least, I can't find the sequence which enables it). Another step to making screen transparent is to set the TERM to something other than "screen".

strager 2009-02-02 01:33:39

I suggest moving your update (the correct answer) to the top of your post, or removing the rest of the content.

strager 2009-02-02 01:34:19

Good idea, thanks. Interested parties who read the above comments can go look at the revision history. :)

Greg Hewgill 2009-02-02 01:38:54

Answer 2

A:

Maybe just set the escape character in .screenrc to an obscure character from the ASCII table which cannot by typed on a keyboard. I think the character 176 would be an example (or try any other one outside the normal range):

escape ^°°

Just put it in your .screenrc file, and your users won't be able to access any screen functionality:

perl -e 'print "escape ^", chr(176), chr(176), "\n"' >> .screenrc

2009-02-02 01:14:40

How about 0x7F (delete character)?

strager 2009-02-02 01:16:56

You can still type any arbitrary ASCII character, using Alt+nnn or copy and paste. Including chr(0x7F).

Greg Hewgill 2009-02-02 01:28:36

@Hewgill, You can use Alt+nnn on an average terminal?

strager 2009-02-02 01:31:38

@Hewgill, first, they won't even know that there is such a character. Second, even if they know the character, can you do Alt+nnn together with Ctrl?

2009-02-02 01:35:25

@strager: The question didn't say anything about an "average terminal". I had interpreted the question to mean that people would be accessing the application from their normal PC workstations, through something like Putty or other terminal emulator.

Greg Hewgill 2009-02-02 01:41:44

@dehmann: There's no need to use Ctrl, since the Alt+nnn method generates ASCII characters based on the number typed. Control characters can be generated by typing Alt+1 through Alt+31 (Alt+0 doesn't seem to generate a null, at least on my XP workstation).

Greg Hewgill 2009-02-02 01:43:41

Answer 3

A:

Preventing the user from using the functionality of Screen is bad form (unless you have a shared login which runs your application).

Instead, make your application deal with the use case you've shown by autologout, warning new connecting users and giving them the option to boot the other user, handling multiple users, etc.

Adam Hawes 2009-02-02 01:39:44

Answer 4

A:

instead of using screen, consider using detachtty/attachtty

Vardhan Varma 2009-02-02 01:53:26

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How do I use GNU Screen transparently

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