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script per cronjob executed several times

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?

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.

Hi,

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

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

Puzzling. Do those processes have children?

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

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

Quote:

Originally Posted by pan64 (Post 4691967)

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"

}

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; }

Quote:

Originally Posted by michaelk (Post 4691972)

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

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

Hi,

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