Nikos Chantziaras <rea...@gmail.com> wrote:
> On 06/07/15 20:01, walt wrote:
> > This is the problem: occasionally bash gets in a state where it stops
> > echoing the characters I type. The commands I type continue to work
> > properly and I can see the output from them but I can't see the commands
> > on the screen as I type them.
>
> I remember having this problem. Especially when aborting programs with
> CTRL+C.
I am interested to know how this can happen.
Note that AFAIK, UNIX would not allow a suitable tty mode that both allows to
implement interactive editing inside a program _and_ letting the kernel do
echoing for the editor at the same time.
This was possible in UNOS in 1980 (the first UNIX clone) and I used it for the
first shell with comand line editor in 1982, but I could not use something
similar on UNIX.
Now I did just run a test on Linux using bash and it turns out that calling
"stty -echo" brings bash into a mode that does not print typed characters in
the command line.
The shells that use my command line editor from 1982 (which is the first shell
with command line editor "bsh" and since December 2006, my portable version of
the Bourne Shell) always use a suitable tty mode for the command line editor -
regardless what the user did set up using stty. It only restores the settings
from the user when a user command is running.
Is bash explicitly implementing a history editor that does not echo characters
in case that "stty -echo" was run? This would be a really bad idea.
Jörg
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