In ksh93u+ I'm using the built-in 'alarm' timer command.

$ alarm --man
Usage: alarm [-r] [varname seconds]

(The original 'alarm' feature may have been experimental
and not documented well, but it was nonetheless useful.)

Just noticed in ksh93u+m that the 'alarm' timer command
doesn't seem to be available; I now get errors like
"alarm: not found"
and
timer.alarm: invalid discipline function

Is there some substitute in ksh93u+m that will replace
that function from the original ksh? (Or something else
to do to get it working?) Or has that feature just been
abandoned in the "u+m" branch?

Janis

On Sun, 17 Mar 2024 10:48:21 -0400, Janis Papanagnou <janis_papanagnou+ng@hotmail.com> wrote:

> In ksh93u+ I'm using the built-in 'alarm' timer command.
>
> $ alarm --man
> Usage: alarm [-r] [varname seconds]
>
> (The original 'alarm' feature may have been experimental
> and not documented well, but it was nonetheless useful.)
>
> Just noticed in ksh93u+m that the 'alarm' timer command
> doesn't seem to be available; I now get errors like
> "alarm: not found"
> and
> timer.alarm: invalid discipline function
>
> Is there some substitute in ksh93u+m that will replace
> that function from the original ksh? (Or something else
> to do to get it working?) Or has that feature just been
> abandoned in the "u+m" branch?

I'm not a ksh user, so don't know much about it. I recommend using the package
"at" for setting alarms and it's not shell dependent.

Regards, Dave Hodgins

On 17.03.2024 18:49, David W. Hodgins wrote:
> On Sun, 17 Mar 2024 10:48:21 -0400, Janis Papanagnou
> <janis_papanagnou+ng@hotmail.com> wrote:
>
>> In ksh93u+ I'm using the built-in 'alarm' timer command.
>>
>> $ alarm --man
>> Usage: alarm [-r] [varname seconds]
>>
>> (The original 'alarm' feature may have been experimental
>> and not documented well, but it was nonetheless useful.)
>>
>> Just noticed in ksh93u+m that the 'alarm' timer command
>> doesn't seem to be available; I now get errors like
>> "alarm: not found"
>> and
>> timer.alarm: invalid discipline function
>>
>> Is there some substitute in ksh93u+m that will replace
>> that function from the original ksh? (Or something else
>> to do to get it working?) Or has that feature just been
>> abandoned in the "u+m" branch?
>
> I'm not a ksh user, so don't know much about it. I recommend using the
> package
> "at" for setting alarms and it's not shell dependent.

Thanks for the suggestion. It reminds me that I obviously
should have made the use case clear, where and how I want
to use the timer. For example; I want to display a turning
"wheel" (or maybe a growing bar) while some operation is
in progress. I might use such a timer in a program called
'busy'. And instead of calling

$ long_running_process arguments

I'd call it as

$ busy long_running_process arguments

The program 'busy' could be something like

$ cat ~/bin/busy
typeset busy='/-\|'
typeset -i i=0
alarm -r timer +0.25
function timer.alarm { print -u2 -f "%c\b" -- "${busy:i++%4:1}" ;}
( "$@" & wait )
unset timer

with 'alarm' and 'timer.alarm' used as supported by ksh93u+.

I suppose the 'at' command is not suited for such purposes.

Janis

On Sun, 17 Mar 2024 14:15:11 -0400, Janis Papanagnou <janis_papanagnou+ng@hotmail.com> wrote:

> On 17.03.2024 18:49, David W. Hodgins wrote:
>> On Sun, 17 Mar 2024 10:48:21 -0400, Janis Papanagnou
>> <janis_papanagnou+ng@hotmail.com> wrote:
>>
>>> In ksh93u+ I'm using the built-in 'alarm' timer command.
>>>
>>> $ alarm --man
>>> Usage: alarm [-r] [varname seconds]
>>>
>>> (The original 'alarm' feature may have been experimental
>>> and not documented well, but it was nonetheless useful.)
>>>
>>> Just noticed in ksh93u+m that the 'alarm' timer command
>>> doesn't seem to be available; I now get errors like
>>> "alarm: not found"
>>> and
>>> timer.alarm: invalid discipline function
>>>
>>> Is there some substitute in ksh93u+m that will replace
>>> that function from the original ksh? (Or something else
>>> to do to get it working?) Or has that feature just been
>>> abandoned in the "u+m" branch?
>>
>> I'm not a ksh user, so don't know much about it. I recommend using the
>> package
>> "at" for setting alarms and it's not shell dependent.
>
> Thanks for the suggestion. It reminds me that I obviously
> should have made the use case clear, where and how I want
> to use the timer. For example; I want to display a turning
> "wheel" (or maybe a growing bar) while some operation is
> in progress. I might use such a timer in a program called
> 'busy'. And instead of calling
>
> $ long_running_process arguments
>
> I'd call it as
>
> $ busy long_running_process arguments
>
> The program 'busy' could be something like
>
> $ cat ~/bin/busy
> typeset busy='/-\|'
> typeset -i i=0
> alarm -r timer +0.25
> function timer.alarm { print -u2 -f "%c\b" -- "${busy:i++%4:1}" ;}
> ( "$@" & wait )
> unset timer
>
> with 'alarm' and 'timer.alarm' used as supported by ksh93u+.
>
> I suppose the 'at' command is not suited for such purposes.

For that use case, I'd use a loop in a separate script with "sleep 0.5s". Have
the main script start it in the background, and kill it when the process is done.
The script containing the loop could create a pid file so the main script knows
what process to kill, or have the main script create a temp file, pass the name
to the loop script, and have the loop script exit after the main script deletes
the temp file.

Regards, Dave Hodgins

On 2024-03-17, Janis Papanagnou <janis_papanagnou+ng@hotmail.com> wrote:
> The program 'busy' could be something like
>
> $ cat ~/bin/busy
> typeset busy='/-\|'
> typeset -i i=0
> alarm -r timer +0.25
> function timer.alarm { print -u2 -f "%c\b" -- "${busy:i++%4:1}" ;}
> ( "$@" & wait )
> unset timer
>
> with 'alarm' and 'timer.alarm' used as supported by ksh93u+.
>
> I suppose the 'at' command is not suited for such purposes.

Remember how I rigged something up in the Basta project to spontaneously
update the clock in the status line, while the shell is waiting for
input or running scripts?

Forked process periodically killing parent with signal, which has a trap
handler for it.

--
TXR Programming Language: http://nongnu.org/txr
Cygnal: Cygwin Native Application Library: http://kylheku.com/cygnal
Mastodon: @Kazinator@mstdn.ca

On 17/03/2024 20:01, Kaz Kylheku wrote:
> On 2024-03-17, Janis Papanagnou <janis_papanagnou+ng@hotmail.com> wrote:
>> The program 'busy' could be something like
>>
>> $ cat ~/bin/busy
>> typeset busy='/-\|'
>> typeset -i i=0
>> alarm -r timer +0.25
>> function timer.alarm { print -u2 -f "%c\b" -- "${busy:i++%4:1}" ;}
>> ( "$@" & wait )
>> unset timer
>>
>> with 'alarm' and 'timer.alarm' used as supported by ksh93u+.
>>
>> I suppose the 'at' command is not suited for such purposes.
>
> Remember how I rigged something up in the Basta project to spontaneously
> update the clock in the status line, while the shell is waiting for
> input or running scripts?
>
> Forked process periodically killing parent with signal, which has a trap
> handler for it.
>

kill -0 <pid> asks ksh whether that process is still running (rather
than actually sending a signal), so something like ... ?

function busy
{ BUSY_PROG=$1
shift

${BUSY_PROG} $@ &

BUSY_PID=$!

while :
do
kill -0 ${BUSY_PID} 2>/dev/null || break
echo -n .
sleep 1
done

wait %1
return $?
}

On 17.03.2024 19:33, David W. Hodgins wrote:
> On Sun, 17 Mar 2024 14:15:11 -0400, Janis Papanagnou
> <janis_papanagnou+ng@hotmail.com> wrote:
>
>> On 17.03.2024 18:49, David W. Hodgins wrote:
>>> On Sun, 17 Mar 2024 10:48:21 -0400, Janis Papanagnou
>>> <janis_papanagnou+ng@hotmail.com> wrote:
>>>
>>>> In ksh93u+ I'm using the built-in 'alarm' timer command.
>>>>
>>>> $ alarm --man
>>>> Usage: alarm [-r] [varname seconds]
>>>>
>>>> (The original 'alarm' feature may have been experimental
>>>> and not documented well, but it was nonetheless useful.)
>>>>
>>>> Just noticed in ksh93u+m that the 'alarm' timer command
>>>> doesn't seem to be available; I now get errors like
>>>> "alarm: not found"
>>>> and
>>>> timer.alarm: invalid discipline function
>>>>
>>>> Is there some substitute in ksh93u+m that will replace
>>>> that function from the original ksh? (Or something else
>>>> to do to get it working?) Or has that feature just been
>>>> abandoned in the "u+m" branch?
>>>
>>> I'm not a ksh user, so don't know much about it. I recommend using the
>>> package
>>> "at" for setting alarms and it's not shell dependent.
>>
>> Thanks for the suggestion. It reminds me that I obviously
>> should have made the use case clear, where and how I want
>> to use the timer. For example; I want to display a turning
>> "wheel" (or maybe a growing bar) while some operation is
>> in progress. I might use such a timer in a program called
>> 'busy'. And instead of calling
>>
>> $ long_running_process arguments
>>
>> I'd call it as
>>
>> $ busy long_running_process arguments
>>
>> The program 'busy' could be something like
>>
>> $ cat ~/bin/busy
>> typeset busy='/-\|'
>> typeset -i i=0
>> alarm -r timer +0.25
>> function timer.alarm { print -u2 -f "%c\b" -- "${busy:i++%4:1}" ;}
>> ( "$@" & wait )
>> unset timer
>>
>> with 'alarm' and 'timer.alarm' used as supported by ksh93u+.
>>
>> I suppose the 'at' command is not suited for such purposes.
>
> For that use case, I'd use a loop in a separate script with "sleep
> 0.5s". Have the main script start it in the background, and kill it
> when the process is done. The script containing the loop could create
> a pid file so the main script knows what process to kill, or have the
> main script create a temp file, pass the name to the loop script, and
> have the loop script exit after the main script deletes the temp
> file.

Yes, I am aware of several methods (like the one you describe or other)
how to tackle the task. I prefer a simple and built-in method, though.

I admit that I am spoiled on that since I had that feature available
in the past, and losing an option and substitute it by other (complex)
ways is something not appearing appealing. :-/

Janis

On 17.03.2024 21:01, Kaz Kylheku wrote:
> On 2024-03-17, Janis Papanagnou <janis_papanagnou+ng@hotmail.com> wrote:
>> The program 'busy' could be something like
>>
>> $ cat ~/bin/busy
>> typeset busy='/-\|'
>> typeset -i i=0
>> alarm -r timer +0.25
>> function timer.alarm { print -u2 -f "%c\b" -- "${busy:i++%4:1}" ;}
>> ( "$@" & wait )
>> unset timer
>>
>> with 'alarm' and 'timer.alarm' used as supported by ksh93u+.
>>
>> I suppose the 'at' command is not suited for such purposes.
>
> Remember how I rigged something up in the Basta project to spontaneously
> update the clock in the status line, while the shell is waiting for
> input or running scripts?
>
> Forked process periodically killing parent with signal, which has a trap
> handler for it.

Yes, I remember. There's a couple options to solve such a task. In case
I have a simple built-in method available I'd prefer that, though.

Janis

On 3/17/24 11:51 PM, Janis Papanagnou wrote:
> On 17.03.2024 21:01, Kaz Kylheku wrote:
>> On 2024-03-17, Janis Papanagnou <janis_papanagnou+ng@hotmail.com> wrote:
>>> The program 'busy' could be something like
>>>
>>> $ cat ~/bin/busy
>>> typeset busy='/-\|'
>>> typeset -i i=0
>>> alarm -r timer +0.25
>>> function timer.alarm { print -u2 -f "%c\b" -- "${busy:i++%4:1}" ;}
>>> ( "$@" & wait )
>>> unset timer
>>>
>>> with 'alarm' and 'timer.alarm' used as supported by ksh93u+.
>>>
>>> I suppose the 'at' command is not suited for such purposes.
>>
>> Remember how I rigged something up in the Basta project to spontaneously
>> update the clock in the status line, while the shell is waiting for
>> input or running scripts?
>>
>> Forked process periodically killing parent with signal, which has a trap
>> handler for it.
>
> Yes, I remember. There's a couple options to solve such a task. In case
> I have a simple built-in method available I'd prefer that, though.
>
> Janis
>

I think several OSes have a tool called 'progress' which sort of
functions as you've described; NetBSD does natively. Having it built-in
would be better though. Was 'alarm' removed in ksh93? I don't see it
on the NetBSD pkgsrc version.

On 18.03.2024 15:14, Arti F. Idiot wrote:
>
> I think several OSes have a tool called 'progress' which sort of
> functions as you've described; NetBSD does natively.

Oh, I wasn't aware that there's some OS specific standard for that.

> Having it built-in would be better though. Was 'alarm' removed in
> ksh93?

It was (still is) there in [official] ksh93u+. That was the version
I predominantly used on my platforms.

Meanwhile I've replaced the "u+" version by Martijn Dekker's "u+m"
version. (The latter has less bugs and works much more reliable.)
It's just my recent switch that made me notice that in his branch
there's no 'alarm' available any more.

Janis

On 3/18/24 9:06 AM, Janis Papanagnou wrote:
> On 18.03.2024 15:14, Arti F. Idiot wrote:
>>
>> I think several OSes have a tool called 'progress' which sort of
>> functions as you've described; NetBSD does natively.
>
> Oh, I wasn't aware that there's some OS specific standard for that.
>
>> Having it built-in would be better though. Was 'alarm' removed in
>> ksh93?
>
> It was (still is) there in [official] ksh93u+. That was the version
> I predominantly used on my platforms.
>
> Meanwhile I've replaced the "u+" version by Martijn Dekker's "u+m"
> version. (The latter has less bugs and works much more reliable.)
> It's just my recent switch that made me notice that in his branch
> there's no 'alarm' available any more.
>
> Janis
>

I was mistaken; alarm is in the att-ksh93 pkgsrc package, it's just an
undocumented built-in, apparently because D. Korn felt it it didn't
function consistently. My brief experiments earlier resulted in several
hung sessions. It's an interesting idea though.

Janis Papanagnou <janis_papanagnou+ng@hotmail.com> writes:
> In ksh93u+ I'm using the built-in 'alarm' timer command.
>
> $ alarm --man
> Usage: alarm [-r] [varname seconds]
>
> (The original 'alarm' feature may have been experimental
> and not documented well, but it was nonetheless useful.)
>
> Just noticed in ksh93u+m that the 'alarm' timer command
> doesn't seem to be available; I now get errors like
> "alarm: not found"
> and
> timer.alarm: invalid discipline function
>
> Is there some substitute in ksh93u+m that will replace
> that function from the original ksh? (Or something else
> to do to get it working?) Or has that feature just been
> abandoned in the "u+m" branch?

I know this isn't useful to you, but tcsh has a similar command called
"sched".

https://linux.die.net/man/1/tcsh

For example, `sched 09:00 echo hello` will print "hello" at 9:00.
Scheduled commands run only while the shell is waiting at a prompt for
input. Missed commands are executed at the next prompt.

"""
This mechanism is similar to, but not the same as, the at(1) command on
some Unix systems. Its major disadvantage is that it may not run a
command at exactly the specified time. Its major advantage is that
because sched runs directly from the shell, it has access to shell
variables and other structures. This provides a mechanism for changing
one's working environment based on the time of day.
"""

--
Keith Thompson (The_Other_Keith) Keith.S.Thompson+u@gmail.com
Working, but not speaking, for Medtronic
void Void(void) { Void(); } /* The recursive call of the void */

On 2024-03-18 10:14 a.m., Arti F. Idiot wrote:
>
> I think several OSes have a tool called 'progress' which sort of
> functions as you've described; NetBSD does natively. 

Careful, though. On Linux systems it is unlikely to be installed by
default. And even if it is installed, it's likely to be a very
different 'progress' program than the NetBSD one:

https://github.com/Xfennec/progress

On Mon, 18 Mar 2024 12:39:51 -0700, Keith Thompson wrote:

> Scheduled commands run only while the shell is waiting at a prompt for
> input.

I wonder why shells don’t make use of poll(2) to run things asynchronously
to command input.