This script uses the "festival" speech synthesis app to keep saying the
word hello. Why can't I stop it with ctrl-c? Is there a workaround?

#!/bin/bash
while true; do
echo "hello" | festival --tts
done

--
Dave Farrance

2006-08-19, 18:16(+00), Dave Farrance:
> This script uses the "festival" speech synthesis app to keep saying the
> word hello. Why can't I stop it with ctrl-c? Is there a workaround?
>
> #!/bin/bash
> while true; do
> echo "hello" | festival --tts
> done

Yes, bash has a funny way of handling sigint. bash will only
exit upon receiving a SIGINT if the current command was killed
by that sigint as well (apparently).

So, if "festival" ignores the sigints, it will not exit.

You can try:


#! /bin/bash -
while :; do
echo "hello" | festival --tts &
wait
done

Then, the CTRL-C will interrup the "wait" instead of festival
(which will continue running).

Or:

#! /bin/bash -
trap 'exit 1' INT
while :; do
echo "hello" | festival --tts
done

This way, bash will still block the SIGINT but will execute its
handler (exit 1) when festival finishes.

--
Stéphane

Stephane CHAZELAS <this.address@is.invalid> wrote:

>Yes, bash has a funny way of handling sigint. bash will only
>exit upon receiving a SIGINT if the current command was killed
>by that sigint as well (apparently).
>
>So, if "festival" ignores the sigints, it will not exit.

Festival doesn't seem to ignore the ctrl-c - it will cancel the word
that it's saying and the script goes on to start the next one.

>You can try:
>
>#! /bin/bash -
>while :; do
> echo "hello" | festival --tts &
> wait
>done
>
>Then, the CTRL-C will interrup the "wait" instead of festival
>(which will continue running).

Thanks. That works.
>
>Or:
>
>#! /bin/bash -
>trap 'exit 1' INT
>while :; do
> echo "hello" | festival --tts
>done
>
>This way, bash will still block the SIGINT but will execute its
>handler (exit 1) when festival finishes.

That works too.

--
Dave Farrance

2006-08-19, 19:30(+00), Dave Farrance:
> Stephane CHAZELAS <this.address@is.invalid> wrote:
>
>>Yes, bash has a funny way of handling sigint. bash will only
>>exit upon receiving a SIGINT if the current command was killed
>>by that sigint as well (apparently).
>>
>>So, if "festival" ignores the sigints, it will not exit.
>
> Festival doesn't seem to ignore the ctrl-c - it will cancel the word
> that it's saying and the script goes on to start the next one.

Then it probably intercepts the SIGINT, and the handler does a
simple exit.

The net result is that the exit status of festival will not show
that it was terminated by a signal, so bash will not exit.

I don't know why bash is behaving like that. It seems to be the
only shell that does.

--
Stéphane