Question about Cron

Hi,

I have a short question about cron which I hope somebody can answer:

Let's say I have this script which runs for a while (has to do a lot of processing).

I want to fire this script every 5 minutes.

If the script is executed at 12:00h and it is still running, will it be executed again at 12:05h? and not wait for the 12:00h to finish.
Or does it wait, and the 12:00h job finishes at 12:12h and starts the new job at 12:15h

(I'd like to know, otherwise I have to build some checking wheter or not the script might be running still. )

TIA.

Quote:

---

If the script is executed at 12:00h and it is still running, will it be executed again at 12:05h?

---

yes

Quote:

---

Or does it wait, and the 12:00h job finishes at 12:12h and starts the new job at 12:15h

---

no

So, you need to analyze ps output to see if your process is still sitting in memory and doing something.

I had a similar problem with my solar monitoring project. (No sun=> no reaction from inverter => waiting until sun comes up...grrr)

I solved it using:

Code:

---

"Some time consuming command"
PID=$!
usleep 1000
if [ -d /proc/$PID ]
then
  kill $PID
fi

---

al37919 and mistraller,

Thank your very much for your input.

I will encapsulate some logic to check wheter or not the script is running. .

thanks again !!..

well, her is an other solution which I use when a script should start, check himself and exit when running.
I use it when the first script can not be killed due to some important jobs like backups and it takes longer.

This script starts and exit himself when pid exists.

if [ ! -n "`pidof yourscript`" ] ; then
echo "script not runing"
#do your job here
else
echo "script running"
#here you do nothing, therefore it ends himself when one instance is running
fi

have fun

Thanks Newbiefan.

all the bits and pieces are falling together now.

Greets,

My cron ron is NOT listed as running process after reboot.
I have done everything like in this tutorial: http://wl500g.info/showthread.php?t=...rmware&page=25
This is my process:

Code:

---

PID  Uid    VmSize Stat Command
    1 admin      632 S  /sbin/init
    2 admin          SW  [keventd]
    3 admin          SWN [ksoftirqd_CPU0]
    4 admin          SW  [kswapd]
    5 admin          SW  [bdflush]
    6 admin          SW  [kupdated]
    7 admin          SW  [mtdblockd]
  57 admin      316 S  telnetd
  62 admin      380 S  httpd vlan1
  67 admin      408 S  syslogd -m 0 -O /tmp/syslog.log -S -l 7
  68 admin      364 S  klogd
  71 admin      520 S  nas /tmp/nas.lan.conf /tmp/nas.lan.pid lan
  73 nobody      440 S  [dnsmasq]
  75 admin          SW  [khubd]
  83 admin      276 S  lpd
  85 admin      260 S  p9100d -f /dev/usb/lp0 0
  89 admin      340 S  waveservermain
  91 admin      344 S  rcamdmain
  95 admin          SW  [usb-storage-0]
  96 admin          SW  [scsi_eh_0]
  103 admin      312 S  infosvr br0
  104 admin      476 S  watchdog
  106 admin      344 S  ntp
  124 admin      440 S  udhcpc -i vlan1 -p /var/run/udhcpc0.pid -s /tmp/udhcp
  125 admin      492 S  upnp -D -L br0 -W vlan1
  127 admin      480 S  dropbear
  129 admin      752 S  dropbear
  130 admin      548 S  -sh
  150 admin          SW  [kjournald]
  151 admin          SW  [kjournald]
  153 admin      392 R  ps
  154 admin      132 R  /usr/sbin/vsftpd

---

This is my post-boot

Code:

---

#!/bin/sh
dropbear
/opt/sbin/cron

---

And this is my rc.unslug

Code:

---

#! /bin/sh

# Start/stop all init scripts in /opt/etc/init.d
# starting them in numerical order and
# stopping them in reverse numerical order
#
if [ $# -ne 1 ]; then
printf "Usage: $0 {start|stop}\n" >&2
exit 1
fi

daemons=`echo $(/usr/bin/dirname $0)/S??*`
[ $1 = "stop" ] && daemons=`echo $daemons | /usr/bin/tr " " "\n" | /usr/bin/sort -r`

for i in $daemons; do

# Ignore dangling symlinks (if any).
[ ! -f "$i" ] && continue

# Write to syslog
logger -t rc.unslung "$1 service $i"

case "$i" in
*.sh)
# Source shell script for speed.
(
trap - INT QUIT TSTP
set $1
. $i
)
;;
*)
# No sh extension, so fork subprocess.
$i $1
;;
esac
done

---

have you checked the log (syslog) after starting cron?

I've just recently gotten a WL-500gP V2 and have flashed the newest oleg on it. I'm currently trying to get cron to execute commands. I have cron running in the ps -A list but it will not execute simple commands.


my current crontab file is

Code:

---

SHELL=/bin/sh
PATH=/sbin:/bin:/usr/sbin:/usr/bin:/opt/sbin:/opt/bin
HOME=/
LOGNAME=admin
1 * * * * date > /tmp/mnt/disc0_3/test.txt
*/1 * * * * /opt/bin/touch /tmp/mnt/disc0_3/test2.txt

---

For some reason this does not work. My router user is the default admin. I even tried creating a cron.allow file in cron.d that has admin in it.

This is driving me nuts and would appreciate any assistance.

the answer you wil find in

PHP Code:

---

man 5 crontab 


---

It should look like:

PHP Code:

---

*/1 * * * * admin /opt/bin/touch /tmp/mnt/disc0_3/test2.txt 


---

Code:

---

SHELL=/bin/sh
PATH=/sbin:/bin:/usr/sbin:/usr/bin:/opt/sbin:/opt/bin
HOME=/
LOGNAME=admin
*/1 * * * * admin date > /tmp/mnt/disc0_3/test.txt
*/1 * * * * admin /opt/bin/touch /tmp/mnt/disc0_3/test2.txt

---

This is my crontab file. I have changed it as al37919 suggested but it still does not work.

man 5 crontab did not help me to figure out what is wrong. From what I gathered from the man page my crontab should work.

Code:

---


./opt/etc/crontab
./opt/etc/cron.d/cron.allow
./opt/etc/cron.d/cron.deny
./opt/etc/cron.d
./opt/etc/crontab.bak
./opt/lib/ipkg/info/cron.prerm
./opt/lib/ipkg/info/cron.control
./opt/lib/ipkg/info/cron.conffiles
./opt/lib/ipkg/info/cron.postinst
./opt/lib/ipkg/info/cron.list
./opt/bin/crontab
./opt/sbin/cron
./opt/man/man1/crontab.1
./opt/man/man8/cron.8
./opt/man/man5/crontab.5
./opt/man/man1p/crontab.1p.gz
./opt/var/cron/crontabs
./opt/var/cron
./opt/var/run/cron.pid
./usr/bin/crontab
./usr/sbin/crond

---

I'm not sure if maybe i'm using a wrong file or something so figured i'd post results of find -depth -name cron*. The cron listed in ps is /opt/sbin/cron.


I am really sorry about requesting so much help but I have just purchased the router and am trying to do the initial setup with out too much luck right now.

are there somthing cron-related in the syslog?
/opt/etc/crontab should have permissions = 600

there's bultin cron already in oleg's firmware
create /opt/etc/crontabs directory to place users' crontabs and /opt/etc/init.d/S10crond (chmod it to +x) to start it

/opt/etc/init.d/S10crond

Code:

---

#!/bin/sh

prefix="/opt"
PATH=${prefix}/bin:${prefix}/sbin:/sbin:/bin:/usr/sbin:/usr/bin
NAME=crond
DAEMON=/usr/sbin/${NAME}
DAEMON_OPTS=""
DAEMON_DIR=/var/spool/cron
CRONTABS_DIR=${DAEMON_DIR}/crontabs
CRONTABS_SRC=${prefix}/etc/crontabs

test -x $DAEMON || exit 0

mkdir -p ${DAEMON_DIR}
if [ ! -h "${CRONTABS_DIR}" ]; then
    ln -s ${CRONTABS_SRC} ${DAEMON_DIR}
fi

if [ -z "$1" ] ; then
    case `echo "$0" | sed 's:^.*/\(.*\):\1:g'` in
        S??*) rc="start" ;;
        K??*) rc="stop" ;;
        *) rc="usage" ;;
    esac
else
    rc="$1"
fi

case "$rc" in
    start)
        echo -e -n "Starting $NAME... "
        if [ -n "`pidof $NAME`" ]; then
            echo -e "        already running."
        else
            echo -e "        done."
            $DAEMON $DAEMON_OPTS
        fi
        ;;
    stop)
        echo -e -n "Stopping $NAME... "
        if [ -n "`pidof $NAME`" ]; then
            echo -e "        done."
            killall $NAME 2> /dev/null
        else
            echo -e "        not running."
        fi
        ;;
    restart)
        "$0" stop
        sleep 1
        "$0" start
        ;;
    *) 
        echo "Usage: $0 (start|stop|restart|usage)"
        ;;
esac

---

/opt/etc/crontabs/admin (user is admin)

Code:

---

#min h d m wday        command
#--------------        ----------------------------------------------
*/30 * * * *        /opt/etc/cron.d/logcleaner
*/1  * * * *        /opt/etc/cron.d/watchdog

---

use crontab -l to list crontabls, and crontab -e to edit current jobs

How can I automatically run a script (cron :confused: ) every time WL500gp made a PPPoE connection (auto connection)?

Please help :D

Quote:

---

Originally Posted by Tomason

How can I automatically run a script (cron :confused: ) every time WL500gp made a PPPoE connection (auto connection)?

Please help :D

---

Well, should be easy - but it depends what you wanna do when there is a valid connection !!:D:D
In any case you must install olegs FW.
At first read and install: http://www.wl500g.info/showthread.php?t=10307

For instance: cron is just a program to handle scheduled tasks from a table (like a spreadsheet).
Example:
02:30 everyday run as admin a program or script
08:00 Mo-Fri run as admin wakeonlan_PCx

But usually a new connection is logged by default.
Tell us which fw and router you are using and what you wanna do with the information.

have fun