#!/usr/bin/perl -w

use strict;
use POSIX "WNOHANG";

Main( @ARGV );
exit( 0 );

sub Spawn {
    my $pid= fork();
    die "Can't fork: $!\n"
      if  ! defined $pid;
    return  $pid   if  $pid;
    exec( @_ );
    die "Can't exec $_[0]: $!\n";
}

sub Sleep {
    my $secs= shift( @_ );
    select( undef, undef, undef, $secs );
}

sub Main {
    die qq[Usage: $0 [work wait [nice]] command [args]
      work  Number of seconds to let "command" work at a time [3]
      wait  Number of seconds to make "command" wait inbetween [6]
      nice  Optional command like "nice" or [nice -20]\n]
      unless  @_;
    unshift @_, qw( 3 6 nice -20 )
      unless  $_[0] =~ /^\d*\.?\d+$/;
    my $work= shift( @_ );
    my $wait= shift( @_ );
    my $kid= Spawn( @_ );
    while(  $kid != waitpid( $kid, WNOHANG() )  ) {
        Sleep( $work );
        kill 'STOP', $kid;
        Sleep( $wait );
        kill 'CONT', $kid;
    }
    exit( $? >> 8 );
}