cron is a task scheduler based on clock time that runs on Linux-based machines.

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2
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1answer
968 views

Make shell script commands to abort after certain timeout

I have often a situation in Linux shell scripts that if a specific command takes too long to run e.g. due to a network problem the shell script should abort running this command. What best practices ...
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2answers
1k views

crontab -e fails to start

whenever I try to run crontab -e I'm getting errors such as: no crontab for banana - using an empty one /tmp/crontab.oeFm1e: Invalid argument Is there any way to edit / install the file?
2
votes
1answer
762 views

Schedule bash script for one time use on OSX

I'm trying to do a little script that, as a function, will take a file and date as input and delete that file on the specified date. So I only need it to schedule to run once, and that's it. I'm on ...
2
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2answers
813 views

wget doesn't see proxy under cron

I'm new to freebsd and have a problem: my script uses wget. when I call it from the command line it works fine and I see the output like this: --2011-09-22 15:55:58-- ...
2
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2answers
2k views

How to set CRON to execute a php file outside of a public html folder?

I have a php file located at, let's say, for example: /data/web/process.php This file is not publicly available (no virtual host is running in that folder, but apache is installed). I need to ...
2
votes
6answers
5k views

How to change wallpaper from command line in KDE 4.3?

Basically question is in title, but let's elaborate a bit: I have KDE 4.3 from Arch Linux. And a script which periodically downloads new wallpaper. So I'd like to set it as current wallpaper from ...
2
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0answers
38 views

Setting up a watchfolder

I want to make a folder that I can put any video file into and have ffmpeg catch it and spit it out as an mp4 and remove the non-mp4 file. I have the following: for f in *.*; do ffmpeg -i input ...
2
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0answers
39 views

Many cron -f processes on unresponsive server

My Debian server had again become unresponsive and needed to be restartet (SSH login impossible, no longer transmitted log data to another server's MySQL Database, no new FTP connections possible, but ...
2
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1answer
169 views

Cron Command for twice a month on Sat @12am

I am wondering if someone can help with the simple but sometimes confusing commands regarding Cron jobs. I would like a cron job to run twice a month on a Saturdat @12am.
2
votes
1answer
93 views

How to make cron perform task every hour during business hours?

I'm trying to make a script run twice every hour during business hours on weekdays, and i have the following in my cron setup: # m h dom mon dow command 8,48 8-17 * ...
2
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0answers
45 views

Performance loss when having too many files in /etc/cron.d?

Is there an amount of files in /etc/cron.d that would lead to worse performance? There are currently about 50 jobs in. In the future there can be up to 200 files in. Am I correct to expect the cron ...
2
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3answers
432 views

Is it possible to run two instances of crond each with its separate cron file?

How to run two instances of crond with different cronjob files? Is it even possible?
2
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2answers
176 views

easy way to automatically retrieve image for desktop background?

I would like to automatically download and replace an image from the NASA website to use as my desktop. in linux i used a cron job to do this, using wget to retrieve the file and a small utility to ...
2
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0answers
774 views

Set the from address on emails from cron/Set default from address for sendmail

As a normal user I can send email, either from the commandline or from PHP. But when a cron job has error output, sending of that email fails (I have a MAILTO=me@example.com at the top of the ...
2
votes
1answer
219 views

cron job not executing

I have a cron job that is supposed to run a script every 15 minutes. */15 * * * * /path/to/script.sh I checked in three hours later and found that the script never ran, even once. Earlier I tried ...
2
votes
2answers
940 views

What are the limitations of crontab?

Hardware considerations aside, are there any limitations on: The maximum number of cron jobs that can be scheduled for a single user The maximum number of CONCURRENT jobs that can be scheduled for a ...
2
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1answer
1k views

/etc/environment and cron

I've got two machines: Fedora and CentOS. And a cronjob 0-59 * * * * env > /home/me/env.log On CentOS I can see that /etc/environment is affecting the output while on Fedora it does not. I want ...
1
vote
2answers
224 views

Who's the cron worker?

If I set cron job for a normal user instead of root, what account execute the scheduled jobs?
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2answers
7k views

crontab - /bin/sh: wget: command not found

I want to set up a crontab on my Macbook Pro running Lion. I run the usual crontab -e and provide a quick job to see if everything is working ok --- */10 * * * * wget -O - -q -t 1 ...
1
vote
1answer
501 views

How to set an offset for cron jobs?

I have seven scripts to launch that take quite long to process, so for my first idea, I wrote my crontab like this: 0 */3 0 0 0 /home/personal/my-script-1 0 */3 0 0 0 /home/personal/my-script-2 0 */3 ...
1
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2answers
417 views

Cron to run command once a day, no mather what time

I want to run a cron command only once a day but not at a specific time as the times my computer is on are unpredictable. Can I do it?
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3answers
2k views

run cron every minute during a specific hour?

Running a cron job every minute is easy, running it at specific minutes past the hour is easy. But is it possible to say "only between 1300 and 1400 run every 1 minute"?
1
vote
2answers
3k views

Schedule a cron job ev X minutes, but exclude it from certain hours in the morning?

Is it possible to make a cron job run say, every 20 minutes, but make it not run for say, 1-4 in the morning.
1
vote
2answers
922 views

os.popen returns empty string when called from cron

I'm trying to get my Raspberry Pi's CPU usage like so: def get_cpu_usage(): return os.popen("top -n1 | awk '/Cpu\(s\):/ {print $2}'").readline().strip() When executed normally, this method ...
1
vote
2answers
2k views

kill and restart process by cron

I've got python script running on a remote machine, periodically it stops responding so I ssh in, kill the existing process, and then restart it. I have to do this several times a week and it's ...
1
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2answers
2k views

JAVA main class not found when using Apple auto-ingest tool

I am trying to setup a cronjob to download my daily and weekly reports from iTunes Connect. I have downloaded Apple's Autoingestion.class and I have made the following shell script to download the ...
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4answers
230 views

Cronjob not working

I've got a simple crontab for ripping my local radio station only when I want: 0 16 * * 0 /root/streamripper.sh 0 17 * * 0 killall streamripper 0 20 * * 0 /root/streamripper.sh 0 21 * * 0 killall ...
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3answers
777 views

The 'which' command returns nothing via cron, but works via console

I've written a little utility in haXe + Neko that needs to execute some GIT commands. To avoid hardcoding the path to the GIT executable I'd like to use the which command to find out where it is. ...
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3answers
1k views

What's wrong with my cron job time schedule?

I'm trying to setup cron jobs for a website hosted on hostmonster.com. When I use the following it runs perfectly: * * * * * But whenever I make changes to these timestamps the script doesn't ...
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2answers
29 views

What happens if shutdown command kills my unison cron job?

I have an Arch linux box at home that I power off quite frequently (the power supply is noisy and it annoys my girlfriend...!). The box has a number of cron jobs running the unison utility, designed ...
1
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1answer
110 views

Why this cronjob wont run

On debian squeeze as user root I add this cronjob with "crontab -e" */1 * * * * root /usr/sbin/ntpdate ptbtime1.ptb.de >> /var/log/ntpdate.log But this cronjob will not run, there is also ...
1
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3answers
3k views

How to run a script at boot time for normal user?

I want to run a bash script at boot time in CentOS 6. I added the script in /etc/init.d/ directory but all these script are run by root. I want to run script for any user.
1
vote
1answer
699 views

Difference between 0,10 and */10 for crontab?

I wanted to run a cron every 10 minutes. What's the difference between the syntax 0,10 and */10?
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2answers
534 views

Why cron saves at /root, when should at /var/www?

Why my cron */1 * * * * /usr/bin/php /var/www/query/query.php &> /root/querylog.log saves query.php output in the /root/ folder? (this script shall save *.txt at its location) It should do so ...
1
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2answers
937 views

Writing a cron job to email myself

How would i write a simple cron job to email myself a message at a certain time? Also is it possible to create a cron job without root access. I'm trying to use my school's server?
1
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4answers
6k views

Disable cron jobs for a specific user

I have a list of jobs in the crontabs for user1, user2. I want to prevent the jobs of user2 from running. I tried listing user2 in cron.deny, but that only prevents him from accessing his crontab. ...
1
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2answers
3k views

Open a terminal from a Crontab

How do I get a gnome-terminal window to open from a crontab? I have tried this: * * * * * /usr/bin/gnome-terminal * * * * * source /home/user_name/.bashrc ; /usr/bin/gnome-terminal * ...
1
vote
2answers
756 views

Cron fails to run bash script

I have bash script #!/bin/sh DTFILE=/etc/daytime.addr DTPORT=13 DAYTIME_ERROR=/tmp/dtm.err function daytime_error(){ if [[ -z $1 ]] then exit 1 fi if [[ -e $DAYTIME_ERROR ]] ...
1
vote
1answer
147 views

scheduling with cronjob to run the php file for only one time

How do I run the php file only once using the cron jobs. i.e., to schedule task to work on 20/06/2015 10:30:00 I tried something like this : 30 10 20 6 ? 2015 /usr/bin/php ...
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2answers
67 views

Running executable from Crontab

I have a file called Exim_queue_size in the root directory. It contains one line: exim -bpc | mail -s'Exim_queue_size' bert@example.com It has had its permissions set with chmod +x , and is thus ...
1
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2answers
598 views

How to find out the reason why a scheduled task hang?

I have scheduled quite a number of tasks in my Windows 7, doing a variety of cron jobs on my machines. I am perfectly sure that these tasks, when run on their own, won't hang. But the problem is ...
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2answers
551 views

cron table mailx caused empty content

I'm using centos 7.0/6.5. The content of /etc/cron.hourly/mail.cron #!/bin/sh log=/var/log/mail.cron.log echo "`hostname` `date`" >> $log 2>&1 mailx -s "test mail" me@example.com < ...
1
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1answer
482 views

Permission Denied in Crontab

I've searched half a day for the answer to this, with no luck. Any assistance will be appreciated. I have a PHP script that modifies the crontab, loads a new cron job, removes some etc. The script ...
1
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2answers
139 views

Executing PHP from crontab

I am utilizing crontab to execute a PHP file as follows: 0 4 * * * /opt/lampstack/php/bin/php /opt/lampstack/apache2/htdocs/tests/test.php I am pretty sure that the file itself is working properly ...
1
vote
1answer
101 views

Why doesn't this cron job run?

My cron job isn't running on my system. Any idea why? % ps aux | grep cron root 4213 0.1 0.2 5548 1496 ? Ss 12:40 0:00 /usr/sbin/crond -n crontab.txt: * * * * ...
1
vote
1answer
360 views

cron executing twice based on day of the week

I have a question. We have a cron job that executed on the 15th of this month: min hr day month day_of_week 35 13 15 6 6 However, it executed again on June 22nd (which was the 6th day of the ...
1
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1answer
340 views

I created Cron but I get errors that don't really understand

I created a crontab like this: 0 22 * * 2 /bin/echo " Hello World " 0 1 * * * /bin/echo " Test" but I receive mails like this, what does it mean? Subject: Cron /bin/echo " Test" ...
1
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1answer
104 views

Found this logentry on my server in the cron.logs, seems to be a hack-attempt, any suggestion for further proceeding?

Here is a logentry, which was executed: mkdir /root/.ssh/;echo "ssh-rsa <some unkown public-key> > /root/.ssh/authorized_keys I'm guessing that I was hacked. Any advice for cleaning up ...
1
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2answers
1k views

How do I run a rake task in cron under a different user?

I'm trying to run a backup script on ubuntu. My problem is that I'm trying to do this using the postgres user account that I setup on ubuntu. I believe having this account run the cron jobs is best ...
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3answers
3k views

What do slashes “/” mean in crontab?

I'm seeing slashes in some crontab examples, I don't understand what they mean? Check this one out for example */10 * * * * /home/ramesh/check-disk-space ...