ksh - map Ctrl-D to exit shell

Question

I would like to know how we can map the keys Ctrl-D in ksh to exit the shell as it does in bash shell.

Not much familiar with key binding in ksh.

Edit

See my comments below.

$ echo $0
bash
$ exit    # I pressed Ctrl-D here, 'exit' string was placed and the shell exited

$> echo $0
ksh
$> Use 'exit' to leave ksh  # I pressed Ctrl-D here, Got this message and returned to the ksh prompt
$> echo $0
ksh
$> cat >> somefile
Some text
$>   # I pressed Ctrl-D here. So this key combination is taken as eof char for file, but not for exit.

So, it's needs Ctrl-D to be mapped to exit the shell? How do I do that?

Answer 1

Ctrl+D (ASCII EOT) already is mapped to exiting the shell, in both vi and emacs modes, as the ksh93 manual page explains. It's quite evidently so from your script capture.

The manual page also explains what others have commented here, that this key only has this effect if the line is empty. (This mimics the standard behaviour of the line discipline in cooked mode.)

What you are missing, which is also explained by the manual page, is that you have the ignoreeof option set on. So the Korn Shell has seen the Ctrl+D on an empty line, and ignored it, printing the very message that you see, to explain that with ignoreeof set on you must explicitly use the exit command.

So forget about stty and trap handlers, as in the other answer; and simply:

set -o noignoreeof

Further reading

• How can I keep control+d from disconnecting my session? — a question wanting to achieve the opposite has an answer that is the opposite

Answer 2

You want the stty command: see how ^D is mapped with stty -a. You can change that to something else with stty eof char: Remove the "eof" setting with stty eof undef

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Untested: you want to read about the trap command in the ksh man page. It might be sufficient for you to set up a handler for the EXIT signal.

# warning: completely untested
exit_handler() { echo "exit"; exit; }
trap exit_handler EXIT