Whats the best prefix/escape sequence for screen or tmux?

Question

Screen goes with CTRL+a. tmux, as developed within screen, uses CTRL+b. Both are also keystrokes in other editors, shells, etc. What do you suggest, which one conflictes at least with other programs?

Answer 1

Ctrl+A is also known to cause problems with Emacs, including Bash in Emacs mode. It sounds like this is not a problem for you.

Ctrl+O is the other option I've seen. Apparantly, this is the default in RatPoison (this is an X window manager that doesn't need a mouse). I've used Ctrl+O when using nested screens: Ctrl+O for the outer one and Ctrl+A for the inner ones. Worked well, but kinda scared my colleagues. :-)

I was just thinking and if you use vi rather than Emacs, there are a few alternatives. Ctrl+G isn't used by much, for instance.

Answer 2

I use a complex system for screen. My default escape is set to \140\140, which is backtick. The Ctrl-A complicates both Emacs and command line editting for me within Zsh, and I dislike Ctrl-O (2 hand operations for most screen actions).

I rebind 's' to screen 1 so that new sessions are created from left to right on the keyboard starting at 1. This allows me to reserve screen 0 for what I consider persistent or reference windows. It's very quick one handed gesture to (backtick)1, (backtick)2, (backtick)3 to swap between windows.

The issue with using backtick in a unix environment is when attempting to cut and paste shell/perl script code. For this reason I bindkey F11/F12 to switch between my escape character.

bindkey -d -k F1        escape ^O^O # bound to F11

bindkey -d -k F2        escape \140\140 # bound to F12

This will swap the escape to Ctrl-O for when I'm doing cut and paste operations. I've found hitting a double tick is simple, and a good trade off for most screen operations.

Answer 3

I think ^\ (a.k.a. ^|) is the best if it's in a convenient position on your keyboard layout. It's uses in other programs are quite rare:

• sending SIGQUIT to a process
• aborting for or while loops in a shell when ^C is intercepted
• toggle-input-method in emacs

I don't know of any other uses.

~/.tmux.conf:

unbind-key C-b
set -g prefix C-\
bind-key C-\ send-prefix

~/.screenrc:

escape ^|^|

Answer 4

Personally, b is just too far away from Ctrl for me. When I use tmux, I alway change the binding from C-b to C-a. The main conflict with C-a is select all, but I have not found this to be a problem with the programs I use tmux with.

Answer 5

I've heard of ` (backtick) being used and then you just have to type it twice for an actual backtick. Might be better for vi users who are used to the action (unless you do the Caps lock thing).

Answer 6

I use Ctrl-Q in tmux and it has worked well so far. I have to mention, though, that it conflicts with shell flow control. By default, Ctrl-Q is used to re-enable output after stopping it with Ctrl-S. Having been surprised by a stuck shell a few times after accidentally hitting Ctrl-S, I have learned not to press Ctrl-S.

(One could also turn off flow control altogether with stty -ixon, or bind different keys to stty start and stty stop.)

# tmux.conf
unbind C-b
set -g prefix C-q

Answer 7

For people who want to use backtick as the escape in tmux, you'll want to add:

unbind C-b
set -g prefix `
bind-key ` send-prefix

That last one is important, else you can't type a backtick for other purposes :-)

Answer 8

As a GNU emacs, zsh, and MS Windows user, I use Control-T. (e.g. in .screenrc:)

escape "^T^T"

Yes Control-T has something bound to it, like the pull down menu in Ubuntu's aptitude, or transpose character in Emacs.

I disregarded C-o because it requires two hands for me.

Answer 9

I like to reserve ^Space for very special/common operations because I find it to be the easiest prefix to type, but right now I'm trying it mapped as the prefix in tmux.

It leaves your fingers free to instantly jump to the command you want to type. Give it a try.

Answer 10

I like the suggestion of binding ctrl-\ as the prefix, but in order to get this to work on Linux Mint 12, I had to escape the place the binding at the bottom. Otherwise, it wouldn't take. See my .tmux.conf here: Using tmux with both emacs and vim