How can I disable keybindings / keybind in GNU screen?

Question

I use iTerm2 on Mac and have customized control + ← and control + → to send hex 0x01 and 0x05 when pressed - which makes the cursor jump to the start and end of the line when typing or editing commands (opposed to one word at a time) - and the alt key plus an arrow makes the cursor move one word at a time.

This works fine on remote linux systems when using SSH, until I start a screen session. The control + → still works fine, but when I try to use control + ← I just get a message in the screen status area:

No other window.

I found documentation that suggested adding these lines to /etc/screenrc or ~/.screenrc would bind the keys to next and previous windows:

bindkey "^[[5D" prev
bindkey "^[[5C" next

And I thought the syntax for unbinding was to use this line with no command:

bindkey "^[[5D"
bindkey "^[[5C"

I've also tried it with as follows:

bindkey "^[[01"
bindkey "^[[05"

None of these things seem to work.

/etc/screenrc is completely unchanged for Ubuntu 16.04 and there is no ~/.screenrc file at the moment ( i.e. nothing non-standard interfering )

How can I unbind this or debug it further to figure out where the hangup is?

Answer 1

The code 0x01 is Control-A which is the default command character in screen, so when you do control + ← twice you have the default action binding of other, i.e. other window, hence the message.

You can change to a different command character, eg Control-b when you start screen:

screen -e^Bb

or you can put in your ~/.screenrc the line

escape ^Bb

Answer 2

You've set Ctrl+Left to send the character ^A (Ctrl+A). This is the same character that Ctrl+A sends, and ^A is the default prefix character for Screen's key bindings.

bindkey "^[[5D" prev in the Screen configuration is useless for two reasons. First, this defines what happens when Screen receives this escape sequence after the prefix character, i.e. after a ^A. Second, ^[[5D is what some terminals send for Ctrl+Left, but you've reconfigured your terminal to send something different (^A).

Instead of making Ctrl+Left send ^A, make it send ^[[1~ or ^[OH (where ^[ is an escape character). Likewise make Ctrl+Right send ^[4~ or ^[OF instead of ^E. These are escape sequences normally sent by the Home and End keys.