Cron is a job scheduler that allows users to run commands periodically.

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408 views

How to set up a cron entry that runs at 00 and 30 after the hour?

I have a cron entry that runs every 30 minutes - */30 * * * * /home/myuser/myscripts.sh How to set this up such that it runs exactly at 30 minute intervals but also exactly at (for example) 3:00 ...
18
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4answers
881 views

Path independent shebangs

I have a script that I want to be able to run in two machines. These two machines get copies of the script from the same git repository. The script needs to run with the right interpreter (e.g. zsh). ...
1
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2answers
141 views

Running a cron job from another shell

I would like cron to run a script from a specific shell (Zsh). I thought the following would work: 00 02 * * * exec zsh; /path/to/script.sh but apparently it doesn't, why? This also made me ...
1
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0answers
27 views

How to block the user for a certain amount of time

Suppose, I am working in X environment, and I want to have an obligatory periodic rest. Is it possible to setup a root cron job, that will block my user for 5 minutes every 45 minutes? I am using ...
3
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5answers
2k views

bash restart mysql when it gone run well in SSH part, but not in cronjob

My system is centos 6.5, I write a simple bash shell to check if mysql is crashed, restart service again. I put it in /home/myspace/mysql.sh chown root:root /home/myspace/mysql.sh then run every ...
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0answers
1k views

why daily cron isn't running on CentOS 6?

I have a daily cronjob set up on CentOS 6 OS which should look after the log rotation job. The file is /etc/cron.daily/logrotate and it's contents are #!/bin/sh /usr/sbin/logrotate ...
1
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1answer
193 views

Why CRONTAB tasks are lost when quit Putty session? [closed]

I logged to remote computer, running under Solaris, using Putty and added some jobs to be run by cron. When I quit console and logged once again all jobs was lost. crontab -l myuser How do I ...
2
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1answer
456 views

Why do deleted files continually reappear?

I've been having a strange issue recently, where I would delete files from a location (i.e. Desktop), and then empty the Trash. However, a day or so later (I'm not sure exactly what triggers it), the ...
1
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1answer
499 views

automate updates with a bash script and cron

I'm trying to automatize the updates of debian system, without making upgrades. Then i'll send an e-mail to me, everytime there is an upgrade available. I've tryied to do it with cron-apt, but i ...
5
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0answers
461 views

CRON Permission Denied [closed]

I have a Debian 7. 3 Server with WebMin installed. I configured a cron job to run every minute as root user, so I run the command crontab -l when I'm logged in as root it shows: * * * * * ...
2
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1answer
114 views

How could I signal to a cron job to skip runs?

I have a cron job that runs every X mins and that I would like to have a way to "signal" it not to do anything if needed. Is there a standard way for this? The only idea I had is to check some ...
4
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2answers
288 views

Does cron know that the instance to be scheduled is already running?

I was wondering if we add a job in the crontab e.g. to run every 5 mins and the job does not actually manage to finish in 5 mins, does the cron daemon know that the previous instance is already ...
0
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1answer
531 views

Getting a Bad Hour Error in crontab

I am getting Bad Hour error for below peice of code in crontab */05 17-05 * * * wget -q -O /dev/null "http://abcd/cron/abcd" Is there any issue with this. I want the cron to run from evening 5 PM ...
0
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1answer
548 views

Cron task starts at 5:30 and runs every 5 mins once

I want to run a crontab cron job which start at 5:30 AM and runs every 5 mins. How do i set it up in Linux? I am able to give like below. But how do i make it 5:30 ? */05 5-16 * * *
2
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1answer
100 views

Accidentally typed crontab with just the dash

What happens when I type just "crontab -"? The "e" didn't take before I hit Enter. It just moved the cursor to the next line and I had to Ctrl+C to exit, but I'm not sure what it did exactly. I'm on ...
2
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1answer
2k views

cronjob for automatic DB backup to date prefixed file

I am using the latest Linux Mint. I was wondering if it's possible to create a special cronjob for a database backup. In my /etc/cronjob file I have the following code: # Minute Hour Day of ...
0
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1answer
120 views

Can continually assigning a variable in a shell script cause a memory leak?

I've written a short script to copy Apache's server status to a log: #Save date and time to a variable dt=$(date) #Echo date and time to the log file as it's not included in server-status echo "Time ...
1
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1answer
490 views

Cron: Client does not have permissions to send as this sender

Platform: Arch Linux Cron: cronie Mail: msmtp I discovered that sending cron output to a mailbox hosted by Office 365 produced the following error, even though sending mail through the CLI was ...
1
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1answer
204 views

Cron task in graphic interface

I need to open one (or more) browser tab periodically and I decided to use cron. The command in the shell (bash) that correctly executes this task is chromium-browser http://mysite.com. If I type it, ...
0
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2answers
99 views

How can I ensure that a custom environment variable is set before cron runs a task?

I recently experienced a logwatch issue that is fixed by running export DATE_MANIP=DM5. cron seems to forget this when I logout (presumably because it's not saved). Where can I add this custom ...
5
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3answers
229 views

Is any extended logging available for cron jobs?

I have 3 scripts under /etc/cron.daily. My cron logs are written in /var/log/cron. The below is an entry for the above cron that has run. (root) CMD (run-parts /etc/cron.hourly) Here the stdout or ...
2
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1answer
211 views

cron midnight 00 24 or 00 00? [closed]

My current crontab looks like this: 00 00 * * 1-5 "/home/user/script.sh" But it seems like it is not being triggered, all others are triggering fine except the one running at midnight. What is the ...
3
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1answer
92 views

What's the easiest way to set up a 2-hour alarm?

I want my computer to play some given .mp3 every 2 hours. I want it to run at startup, and be modifiable with a given .conf file. The choice of .mp3 will also be in the .conf file. The reason is, I ...
3
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2answers
90 views

How to run a command as if it is called from cron

I write a script and set it as a cron job. But due to a difference of environment variables it doesn't work as it should be. In that case I change a little bit with crontab -e and set a cron job time ...
9
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1answer
204 views

Cronjob to Run and then Terminate

I want to add a cron entry that does something like: 00 00 * * * * /tmp/script.sh Is there something I can add to the end of the line, so that when it is finished, it will remove the line out of my ...
1
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1answer
263 views

Why does redirection in crontab result in a zero byte file?

System: Xubuntu 13.10 When I have this crontab entry */5 * * * * cat /home/dbk/.bash_aliases &> /home/dbk/Desktop/junk junk has a byte size of 0. Running $ cat /home/dbk/.bash_aliases ...
0
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2answers
68 views

Cron Job - Log Each Minutes Activity [duplicate]

I have some cron jobs set up to run, some of them each minute. I know I can log them to text files by simply putting php /path/to/file.php > /var/logs/something.txt but can I do this every minute? ...
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0answers
2k views

Trying to kill cron job processes found by “ps ax | grep keyword” logged in as pi user

I'm trying to kill several processes from the command line logged into the pi as the user pi. All of the processes have been started by cronjobs, so they should belong to the root user. I'm running ...
2
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1answer
137 views

Solaris cron ignoring mail aliases?

As a Solaris user, I want cron jobs generated emails for the localuser@server to be forwarded to my myuser@sample.com email account, so that I read only one inbox. To resolve this I have forwarded ...
1
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1answer
2k views

As root, how can I list the crontabs for all users?

I have a script being run automatically that I can't find in the crontab for the expected users, so I'd like to search all users' crontabs for it. Essentially I want to run a crontab -l for all ...
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3answers
68 views

variables in crontab [duplicate]

On our linux server we have a lot of entries. Many entries look like this: 15 13 * * 3 /very/long/path/to/binary/run.sh ... These entries would be easier to maintain if I could write: 15 13 * * ...
2
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2answers
753 views

How come crontab -e is different from less /etc/crontab?

Im pretty new to unix and crons, I was currently about to try to add crons to an existing cron file. I read you could do this with crontab -e. The confusing thing to me is just that crontab -e shows ...
1
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1answer
89 views

Help with “crontab -e” [duplicate]

I'm trying to learn a little about cron and would appreciate some help. I edited crontab -e to have this line: */10 * * * * /usr/bin/touch /home/dkb/Desktop/test.txt It works and I see ...
7
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7answers
2k views

cron Vs. sleep - which is the better one in terms of efficient cpu/memory utilization?

The Case: I need to run some commands/script at certain intervals of time and for this I have two options - 1. set up a cron-job or, 2. implement a loop with sleep in the script itself. Question: ...
3
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3answers
251 views

Setting up a cron for every 30 hours in Debian

*/30 */30 * * * python /root/get_top.py I'm trying to run a script every 30 hours and 30 minutes. Is the syntax above proper for that? I've had multiple people tell me that */30 is not a valid ...
0
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1answer
53 views

Crontab in Daylight Savings

This weekend with daylight savings, we had a situation that when the system clock hit 3:00am from the jump, we had hundreds of processes fire off out of the crontab. Everything I'm reading says that ...
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1answer
89 views

Is there a better way to stop and restart Apache server every 30 minutes? [closed]

I have to stop and restart Apache every 30 minutes in order to avoid it becoming extremely slow over time. The cron job that I use as follows: @echo off rem Launch google.com, wait 2 seconds, then ...
0
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2answers
327 views

Backup of svn repository and mysql database on daily basis

How do I instruct Ubuntu 13.10 server to: zip svn repository dump mysql database into .sql script tar both files copy backup tar onto sdb disk Are there any premade tools for such kind of ...
2
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2answers
275 views

Running cron.daily in parallel

Being able to put a script in /etc/cron.daily is really nice because I can do it easily from a configuration management system or a package. However, my understanding is that all the entries in ...
2
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4answers
666 views

Cron not running my script

I'm not sure why but my app never executes when I reboot my machine. In crontab > crontab -e I see @reboot /root/myscriptname.sh The file is #!/bin/bash nohup mono-sgen /root/myapp.exe ...
1
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1answer
355 views

Use /etc/init.d/fetchmail with the personnal ~/.fetchmailrc

Now, I have two users in my system using fetchmail with a personal ~/.fetchmailrc and syncing there mails with the command fetchmail -kv --uidl -m '\''/usr/bin/procmail -d %T'\ (In a cron but this ...
1
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0answers
33 views

Why am I not receiving any system e-mails? [closed]

In my crontab, I have the following: * * * * * sh /home/rimmer/test.sh In /home/rimmer/test.sh I have the following: #!/bin/bash echo 'test'; I have also set chmod +x /home/rimmer/test.sh, of ...
2
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3answers
2k views

Installing crontab using bash script

I have created a script to install two scripts on to the crontab. #!/bin/bash sudo crontab -l > mycron #echo new cron into cron file echo "*/05 * * * * bash ...
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1answer
235 views

Logrotate not picking up or acting on new configuration file

I had a logrotate configuration file set up for a log (let's call it Log1). It is working fine and the log is rotating everyday as expected. Yesterday I cloned this set up and modified it for three ...
1
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1answer
117 views

Debian, nonroot, cron, bash script and rebooting at specific time

As nonroot user, how can I schedule a reboot every day at 4:30am? 30 04 * * * /home/user/scripts/reboot.sh As a nonroot normal user, I'm sure the system won't allow me to use the reboot command. ...
1
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1answer
107 views

crontab is giving only 2045 lines of output instead of 6000 lines

I am executing one shell script with crontab which has to give more than 6000 lines output only it is giving output up to 2045 lines then coming out. when I run that shell script it is working fine ...
1
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1answer
54 views

Is it possible to use the at command to schedule a job to run at a given timestamp?

I want to schedule a file to run using the at command, as described in this tutorial. I see that the at command supports the posix format -- but I don't see any mention of timestamps. Surely it is ...
0
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2answers
3k views

Cron job is not working [closed]

i have a cron job center code hereonfigured at var/spool/cron/testuser, Am calling "adindex.sh" file from there. Am getting results when am directly put the command directly in prompt(php and sh), ...
2
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2answers
758 views

How can a normal user trigger a root cron task to execute immediately, without delay?

I have a root cron task that runs every day. But I want to allow normal users to request that it run immediately, if they so wish. It is a harmless process and it can run as often as needed and these ...
4
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2answers
5k views

How to find a cron job if you know the specific time it runs?

I've been using kSar to look at my servers resource use. There is a definite spike in process creation at 4:04AM daily. Cron seems to define the interval they should be run, but not the specific time ...