Re: Ctrl+4 means SIGQUIT+coredump, where is this documented, what more shortcuts are there?

On 10/31/18 10:54 AM, Stuart Henderson wrote:
> On 2018-10-31, Tinker <t1nkr@protonmail.ch> wrote:
>> Hi,
>>
>> When in "cat" or "dd if=/dev/zero of=/dev/zero" or "gzip < /dev/zero >
>> /dev/zero", if I press ctrl+4, the program coredumps.
>>
>> Doing it in ksh or sh has no effect though.
>>
>> This is in OpenBSD 6.4 AMD64 from Putty on Windows.
>>
>> The console interaction looks like this:
>>
>> $ cat
>> ^\Quit (core dumped)
>>
>> $
>>
>>
>> Is ctrl+4 a universal SIGQUIT+coredump shortcut?
>>
>> Where are the other shortcuts apart from ctrl+C, ctrl+Z, ctrl+D,
>> documented?
>>
>> Tinker
>>
>>
>
> No idea how ^4 is mapped to ^\, but for some reason it is, and this
> the default for "quit", see "stty -a".
>
> This is a useful sequence to interrupt boot if you weren't quick enough
> to "boot -s" to enter single-user mode.
>
>

You can also find more details in the termios(4) man page, specifically the Special
Characters section.

- Aner