[billforsternz]

I is tab ('\x09' or '\t') and J is new line ('\x0a' or '\n'). These Ctrl combinations follow a predictable linear mapping to the control character section of the ASCII table. Basically Ctrl subtracts 0x40, so I is 0x49, Ctrl I is 0x09.

[__mharrison__]

TIL: Ctrl subtracts 40.

(28 year emacs user)

[pjz]

on a linux box try `man ascii`

[__mharrison__]

There are lots of man pages. This one doesn't mention Ctrl being minus 40. Not sure what the point is.