Bug#182331: ITP: sleepenh -- an enhanced sleep program for using in shell scripts

[Pedro Zorzenon Neto <pzn@terra.com.br>]

> 
> You mean this does nothing but
> 
> while sleep n; do command; done
> 
> ?
> 
> -- 
> 	Falk

Hi Falk,

  It just sleeps some time from current-time or from some initial-time,
with microsecond resolution. If you run it several times, the final
sleep will be the sum of all the sleeps (without cumulative errors
due to several calls to the program) <- this is the feature that I
needed and did not find in any other sleep program.

  I'll paste some manpage content. If you have any other question, don't
hesitate do write again.

  Sorry for not describing it well in the ITP.

    Pedro

-- manpage

NAME
       sleepenh - an enhanced sleep program.

SYNOPSIS
       sleepenh [initial-time] sleep-time

DESCRIPTION
       sleepenh  is  a  program  that can be used when there is a
       need to execute some functions  periodically  in  a  shell
       script.  It  was  not  designed to be acurate for a single
       sleep, but to be acurate  in  a  sequence  of  consecutive
       sleeps.
       After  a  successfull  execution, it returns to stdout the
       timestamp it finished running, that can be  used  as  ini­
       tial-time to a successive execution of sleepenh.

OPTIONS
       There  are  no  command  line  options. Run it without any
       option to get a brief help and version.

ARGUMENTS
       sleep-time is a real number in seconds, with  microseconds
       resolution  (1  minute, 20 seconds and 123456 microseconds
       would be 80.123456).
       initial-time is a real number in seconds,  with  microsec­
       onds  resolution.  This  number  is  system  dependent. In
       GNU/Linux systems, it is the number of seconds since  mid­
       night  1970-01-01  GMT.  Do not try to get a good value of
       initial-time. Use the value suplied by a  previous  execu­
       tion of sleepenh.
       If  you don't specify initial-time, it is assumed the cur­
       rent-time.

USAGE EXAMPLE
       Supose you need to send the char 'A' to  the  serial  port
       ttyS0 every 4 seconds. This will do that:

          #!/bin/sh
          TIMESTAMP=`sleepenh 0`
          while true; do
            # send the byte to ttyS0
            echo -n "A" > /dev/ttyS0;

            # just print a nice message on screen
            echo -n "I sent 'A' to ttyS0, time now is ";
            sleepenh 0;

            # wait the required time
            TIMESTAMP=`sleepenh $TIMESTAMP 4.0`;
          done