crond als Shellskript

#!/bin/sh

# crond replacement

CRONTAB=/var/etc/crontab
# crontab format
# +---------minute         00-59
# | +-------hour           00-23
# | | +-----day of month   01-31
# | | | +---month          01-12 
# | | | | +-day of week    1-7 
# | | | | |                                                              
# * * * * * command

while true
do
  remain=$(date +%S|sed 's/^0//')
  sleep $((60-remain))
  set $(date '+%M %H %d %m %w')
  while read minute hour day month wday command
  do
    runit=""
    if [ "${minute###}" != "$minute" ] 
    then
      continue
    fi 
    [ "$minute" = "$1" ] || [ "$minute" = "*" ] && runit=$runit"M"
    [ "$hour" = "$2" ] || [ "$hour" = "*" ] && runit=$runit"H"
    [ "$day" = "$3" ] || [ "$day" = "*" ] && runit=$runit"d"
    [ "$month" = "$4" ] || [ "$month" = "*" ] && runit=$runit"m"
    [ "$wday" = "$5" ] || [ "$wday" = "*" ] && runit=$runit"w"
    if [ "$runit" = "MHdmw" ]
    then
      log="/tmp/log-$(date +%Y%m%d)"
      echo "$(date) running $command" >> $log
      $command >>$log 2>&1 &
    fi 
  done < $CRONTAB
done

    if [ "${minute###}" != "$minute" ] 
    then
      continue
    fi

if [ "${minute###}" != "$minute" ]

if [ "${minute#'#'}" != "$minute" ]