Re: at based alarm.

[peter@easthope.ca]

    From: davidson <davidson@freevolt.org>
    Date: Sun, 11 Feb 2018 10:31:25 +0000 (UTC)
> In the "wake" script, you could start xterm with the -e option (and
> put the remainder of your "wake" script in a separate "wake-aux"
> script, I guess):

OK, thanks.  wake is now simplified to this.

peter@computer:~$ cat wake
#!/bin/bash
  input=""
  until [[ $input != "" ]] ; do
    echo Beginning until loop.
    /usr/bin/play /home/peter/ring.wav
    read -n 1 -t 4 input
  done

Test the script.
peter@computer:~$ xterm -e ./wake
Yes, it works for bash.  Appears [[ or read is not available in dash.

Also tried defining a function in .bashrc.
peter@computer:~$ declare -f wake
wake ()
{
  input=""
  until [[ $input != "" ]] ; do
    echo Beginning until loop.;
    /usr/bin/play /home/peter/ring.wav;
    read -n 1 -t 4 input;
  done
}

Test the function.
peter@computer:~$ wake
Yes, it works .

Test the function with xterm.
peter@computer:~$ xterm -e wake
The xterm window opens and immediately closes.  A function 
is not an acceptable option?

Try the alarm using the working script.
peter@computer:~$ echo "xterm -display :0 -e ./wake" | at 6:30

The xterm window doesn't open but there is no error message 
to the originating terminal or to syslog.

I need to understand why "xterm -display :0 -e ./wake" fails for at 
but works interactively.

> I ask about your intent above because this next line...
> 
>     until [[ $input != "" ]] ; do
> 
> ...employs the new-fangled Korn shell/Bash conditional test '[[',
> instead of the old-fangled test builtin '['.

bash is now specified.  I'd prefer "test" rather than "[[" but haven't 
found how to make it work.  In common use, "[" and "[[" are delimiters. 
"test" is a better keyword.

Thanks,                          ... P.



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