script per cronjob executed several times

the_bigbalu · 05-31-2012, 03:21 AM

Hi there,

I made a script for copy files to an directory. It looks like:

Code:

date=`date +%F`
sdir=/home
backupdir=/mnt/backup
ddir=$backupdir/$date

mkdir $ddir

rsync -avz $sdir $ddir

#Packe die Daten um Festplattenplatz zu sparen
if [ $? = 0 ]
then
        tar cvjf $ddir.tar.bz2 $ddir
        rm -rf $ddir
else
        exit 50
fi

When i run this script, one task is running. If i put this into crontab, there a 50 copyjobs und 50 packagejobs. What can i do to run this script on a time (cron) and only one task?

catkin · 05-31-2012, 03:25 AM

What is the cron job line? There is nothing in the script to create 50 instances so it must be the cron job that does so.

the_bigbalu · 05-31-2012, 03:42 AM

Hi,

the Cronjob looks like this:
* 23 * * * /root/script/backup.sh

the_bigbalu · 05-31-2012, 06:30 AM

after the cronjob started, it looks like:

Code:

root@server:~# ps aux | grep backup
root     25540  0.0  0.0   2556  1016 ?        Ss   May30   0:00 /bin/bash /root/script/backup.sh
root     25575  0.0  0.0   2556  1044 ?        Ss   May30   0:00 /bin/bash /root/script/backup.sh
root     25603  0.0  0.0   2556  1040 ?        Ss   May30   0:00 /bin/bash /root/script/backup.sh
root     25656  0.0  0.0   2556  1020 ?        Ss   May30   0:00 /bin/bash /root/script/backup.sh
root     25680  0.0  0.0   2556  1040 ?        Ss   May30   0:00 /bin/bash /root/script/backup.sh
root     25710  0.0  0.0   2556  1044 ?        Ss   May30   0:00 /bin/bash /root/script/backup.sh
root     25743  0.0  0.0   2556  1044 ?        Ss   May30   0:00 /bin/bash /root/script/backup.sh
root     25778  0.0  0.0   2556  1040 ?        Ss   May30   0:00 /bin/bash /root/script/backup.sh
root     25814  0.0  0.0   2556  1016 ?        Ss   May30   0:00 /bin/bash /root/script/backup.sh
root     25874  0.0  0.0   2556  1036 ?        Ss   May30   0:00 /bin/bash /root/script/backup.sh
root     25921  0.0  0.0   2556  1020 ?        Ss   May30   0:00 /bin/bash /root/script/backup.sh
root     25939  0.0  0.0   2556  1040 ?        Ss   May30   0:00 /bin/bash /root/script/backup.sh
root     25973  0.0  0.0   2556  1040 ?        Ss   May30   0:00 /bin/bash /root/script/backup.sh
root     26005  0.0  0.0   2556  1036 ?        Ss   May30   0:00 /bin/bash /root/script/backup.sh
root     26029  0.0  0.0   2556  1044 ?        Ss   May30   0:00 /bin/bash /root/script/backup.sh
root     26070  0.0  0.0   2556  1020 ?        Ss   May30   0:00 /bin/bash /root/script/backup.sh
root     26111  0.0  0.0   2556  1044 ?        Ss   May30   0:00 /bin/bash /root/script/backup.sh
root     26143  0.0  0.0   2556  1040 ?        Ss   May30   0:00 /bin/bash /root/script/backup.sh
root     26190  0.0  0.0   2556  1020 ?        Ss   May30   0:00 /bin/bash /root/script/backup.sh
root     26216  0.0  0.0   2556  1020 ?        Ss   May30   0:00 /bin/bash /root/script/backup.sh
root     26245  0.0  0.0   2556  1016 ?        Ss   May30   0:00 /bin/bash /root/script/backup.sh
root     26274  0.0  0.0   2556  1040 ?        Ss   May30   0:00 /bin/bash /root/script/backup.sh
root     26302  0.0  0.0   2556  1040 ?        Ss   May30   0:00 /bin/bash /root/script/backup.sh
root     26362  0.0  0.0   2556  1044 ?        Ss   May30   0:00 /bin/bash /root/script/backup.sh
root     26386  0.0  0.0   2556  1020 ?        Ss   May30   0:00 /bin/bash /root/script/backup.sh
root     26443  0.0  0.0   2556  1016 ?        Ss   May30   0:00 /bin/bash /root/script/backup.sh
root     26465  0.0  0.0   2556  1028 ?        Ss   May30   0:00 /bin/bash /root/script/backup.sh
root     26505  0.0  0.0   2556  1016 ?        Ss   May30   0:00 /bin/bash /root/script/backup.sh
root     26531  0.0  0.0   2556  1016 ?        Ss   May30   0:00 /bin/bash /root/script/backup.sh
root     26575  0.0  0.0   2556  1044 ?        Ss   May30   0:00 /bin/bash /root/script/backup.sh
root     26603  0.0  0.0   2556  1016 ?        Ss   May30   0:00 /bin/bash /root/script/backup.sh
root     26646  0.0  0.0   2556  1032 ?        Ss   May30   0:00 /bin/bash /root/script/backup.sh
root     26671  0.0  0.0   2556  1020 ?        Ss   May30   0:00 /bin/bash /root/script/backup.sh
root     26723  0.0  0.0   2556  1016 ?        Ss   May30   0:00 /bin/bash /root/script/backup.sh
root     26765  0.0  0.0   2556  1016 ?        Ss   May30   0:00 /bin/bash /root/script/backup.sh
root     26786  0.0  0.0   2556  1016 ?        Ss   May30   0:00 /bin/bash /root/script/backup.sh
root     26815  0.0  0.0   2556  1040 ?        Ss   May30   0:00 /bin/bash /root/script/backup.sh

catkin · 05-31-2012, 07:17 AM

Puzzling. Do those processes have children?

pan64 · 05-31-2012, 07:19 AM

I would make a pid file (script creates and removes at the end).
When it exists script will do nothing, just exit.

also you can add set -xv and redirect output (and stderr) to a logfile to see what's happening

michaelk · 05-31-2012, 07:31 AM

Quote:

* 23 * * * /root/script/backup.sh

The * in the minute column means it will run every minute between 2300 - 2359. I would expect to see 60 jobs but it depends on how long it takes to perform the backup.

This will run your job once.
00 23 * * * /root/script/backup.sh

catkin · 05-31-2012, 07:59 AM

Quote:

Originally Posted by pan64

I would make a pid file (script creates and removes at the end).
When it exists script will do nothing, just exit.

Here's a simple function to implement that (assumes $pidfile contains the name of the PID file)

Code:

# Check and write PID file
function PIDfile {
    local cmd my_name PID
    if [[ -f "$pidfile" ]]
    then
        my_name="${0##*/}"
        PID=$(cat "$pidfile")
        cmd=$(ps --pid "$PID" --format cmd --no-headers)
        if [[ "${cmd##*/}" = "$my_name" ]]
        then
            echo "$my_name is already running with PID $PID" >&2
            exit 1
        else
            echo "Refreshing stale PID file, $pidfile" >&2
        fi
    fi
    echo $$ > "$pidfile"
}

unSpawn · 05-31-2012, 01:57 PM

This doesn't cover every aspect but stops the script in one instead of seventeen lines ;-p :

Code:

[ $(pgrep -f /root/script/backup.sh|head -1) -eq $$ ] || { logger "Already running, exiting."; exit 0; }

suicidaleggroll · 05-31-2012, 05:37 PM

Quote:

Originally Posted by michaelk

The * in the minute column means it will run every minute between 2300 - 2359. I would expect to see 60 jobs but it depends on how long it takes to perform the backup.

This will run your job once.
00 23 * * * /root/script/backup.sh

*ding* *ding* *ding*
We have a winner

Although making/checking a PID is a good idea as well.

the_bigbalu · 06-01-2012, 01:14 AM

Hi,

merci for those good answers! :-) Thank you very much!