Cron is used to execute scheduled commands. It acts as a task scheduler on Linux and UNIX systems which will execute commands at specified times set by the user. Cron has a great deal of customization and is often used on server environments where common tasks are run on a regular basis.

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1k views

Is there a programmable way to tell if the screen is locked?

I have lots of stuff in my crontab, including some that talks to my screen. If I'm not there for it to be notifying, I don't really want it to run. Is there a way I can check to see if the computer ...
0
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1answer
71 views

For processes to be up and running all the time

I want my python program sample.py to be always up and running. I have read some things and asked people about ways to do this. So far I have following options - Upstart Cron I am trying things ...
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3answers
1k views

What is the easiest, most effective backup system for Ubuntu Servers?

I'm trying to backup my /var/www/ folder, MySQL, and any other special documents like in the /etc/apache2/ folder. Does anyone have any solutions for backup software? Maybe something that's ...
2
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1answer
1k views

Cron script to detect degraded raid array?

To my surprise, my raid array entered degraded mode some time ago. How can I set up a cron job to warn me? I've tried from the mdadm man page: Running mdadm --monitor --scan -1 from a cron script ...
2
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2answers
344 views

How to store sensitive information (passwords) so it can be accessed by cronjob?

I'm writing an extension to a python program that will need to store passwords and need to access them during non interactive cronjobs (during the user is not logged in). My first approach was to use ...
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1answer
2k views

Cron cannot run gnome-terminal

I set the following cron in my local machine. * * * * * /bin/bash -c /home/JSX/Stuff/J/login-check/open-console.sh The content of open-console.sh is the following:- #! /bin/sh gnome-terminal ...
5
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1answer
385 views

Is it possible to use the 'screen' command to work with files on an encrypted home directory?

So I have an encrypted home directory, set up during install on a server running Ubuntu 12.04 LTS. I attempted to use screen in order to run a script that accesses the data in my home directory after ...
3
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3answers
217 views

How to run a command within a time duration per min/sec?

I want to run a command/shell script say script.sh from 1AM to 2AM per minute. After observing that crontab can't work it out 'per sec' I had to go with 'per min'. Basically, My server.sh file takes ...
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2answers
1k views

Only run CRON job if connected to specific wifi network

I am a newbie to scripting on Linux (Lubuntu), but I would like to make a script that runs a cron job only if my laptop is connected to my home wifi. Is this possible? I guess, I could do something ...
3
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1answer
514 views

scrot (screenshot) cron job not executing

I'm trying to execute a cron job with Scrot (screenshot utility) but it won't work. At first I thought it was a directory problem. I wrote my.png by itself at first, which could have been dropping ...
2
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1answer
4k views

How can I use cron-apt to download and install updates between midnight and 5am?

I have capped data which is essentially free between midnight and 5am. As a result, I would like to set Ubuntu to automatically download updates over that time. It seems that cron-apt is what I need, ...
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4answers
2k views

How do I get this script to run periodically via cron?

I made a script that sends my local sensors temperature to a server in the internet and then I can see a graph of it. Everything works fine when I execute it manully. I have the latest ubuntu version. ...
2
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2answers
1k views

Why isn't cron running my script?

Now I want to use Backup and Whenever gem to automatic backup my database. When I connect the server by ssh as an added user to run backup perform -t my_backup,it works well.But the cron file: 0 22 * ...
3
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1answer
1k views

How to start a never ending script at startup

I'm trying to automatically run a never ending script (so it doesn't return 0 on exit) at startup on my headless ubuntu 12.04 server with no GUI. I have tried @reboot nohup /home/luke/netup.sh & ...
0
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1answer
5k views

Setting MAILTO=“” for cron in Ubuntu

I have tried setting MAILTO="" under /etc/crontab and /etc/default/cron, but I still receive mail notifications from cron. Is there a single place to disable all mail from cron, as opposed to per-task ...
3
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2answers
515 views

rename files inside a folder in real time

Is there a way to rename files inside a folder as they're created? I could run a cron job every few seconds to do something like... find . -name "file.*" -exec sh -c 'echo mv "$1" "$(echo "$1" | sed ...
2
votes
2answers
541 views

add cron job to foreground

I am trying to run a program that pops up a graphical notice to me. As a simple example, I have my cron settings as @hourly xlogo and if I launch xlogo from an interactive command, it works fine. ...
0
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1answer
480 views

setting up anacron for version control update

I store some of my configuration files in version control. Recently I tried to setup a daily anacron job so that I won't have to manually update the files. I have never used cron or anacron before but ...
3
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2answers
6k views

How can I set up a php script to run via cron?

How can I set up a php script to run via cron I've created a file in the cron.d folder with the username as the file name: /etc/cron.d/username Inside of username file I placed the following cron ...
2
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1answer
3k views

Why doesn't this script output to a text file when run from cron?

I have created a Shell Script as below Sample.sh echo "Hi there" I also added cron job in cron tab which is under /etc/crontab as below * * * * * /home/Sample.sh > /home/Sample.txt I have ...
0
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1answer
1k views

Cron service up but apparently not working

I'm trying cron in a Ubuntu VPS with a minimal install, so I had to run apt-get install cron. However, say I run crontab -e and add (as root) the following line: * * * * * date >> /root/datelog ...
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2answers
4k views

How to make a bash script generate a new filename every time it's run?

I'd like to make a .tar file of a particular directory every day of the week. The way I'd like to do it is with a bash script making a tar file every day with crontab. I was wondering, is there a ...
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2answers
3k views

crontab Suddenly Stopped Working

Ok so here is my problem, I recently updated my server and change some jsp files which are used to do automatic announcements. The crontab has all the .sh files listed within it and the .sh files run ...
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1answer
413 views

rsync password problem

I have a python script. In that, I am using rsync for data transfer between two systems. While running, it ask for password for data transfer. So that I create a password-less run by the below ...
4
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1answer
2k views

Why does my computer shuts down itself every morning at 6 AM?

My computer shuts down by itself at a specific time everyday 6:00am. I can't find what's causing it. I'm a long time Windows user and just recently tried Ubuntu. So I don't know anything about Linux ...
0
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1answer
591 views

How to start and stop a task using at command?

I want to start download using aria2c everyday at 02:00 am and stop it at 08:00 am. I know I should use at 02:00 at>aria2c .... I don't know how to tell 'at' to stop it! Actually aria2c stops ...
6
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1answer
5k views

How to start / stop Dropbox at a specific time

I have setup a service on my Ubuntu 10.04.4 LTS server, which works when started and stopped manually using sudo service <service> start etc. However I would like to have the service (dropbox ...
2
votes
2answers
266 views

crontab not working as expected

I'm using ubuntu 12.04 and I want to execute a script every 5 hours . I setup cron with crontab -e and putted * */5 * * * sh /home/cron_script.sh The script is executed every minute. Thanks.
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1answer
10k views

Cron job not executing

I was making a cron job to save my Minecraft world from my ram every 5 minutes. I tested the script and it seems to be working. This is what the script looks like: #!/bin/sh ...
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1answer
1k views

Why does Ubuntu Server run both cron and atd?

From the man pages it appears both do basically the same thing, why have both running on the system at the same time? From the wording in the man pages it looks like cron will repeatedly run programs ...
3
votes
1answer
973 views

Run /etc/cron.daily/apt at a specific time (i.e. without anacron)

I want to setup a cron job to download up-to-date package only at night. But I found that the cron.daily jobs will be run by anacron if it's installed, so if my computer fails to wake-up at night to ...
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1answer
2k views

Cron not sending email notifications

I'm finishing biulding our new server, based on 12.04 32-bit desktop version. I've set up a few cron tasks, that are running as they're supposed. only, I've added the MAILTO = ...
0
votes
1answer
498 views

Cronjob not working

I have added a new line to my crontab file, but this line won't work. This is the code of my crontab file: # Music scrobbler # Every 5 minutes */5 * * * * php -f /var/www/Music/scrobble/index.php # ...
2
votes
2answers
10k views

“command not found” when running a script via cron

I want to run my script in crontab, but I have some problems... In my script I run this command: db2 connect to myDB2 This works fine when I run this as db2inst1 user, but when I run this script ...
0
votes
1answer
110 views

Crontab file is garbled! HELP!

I accidentally deleted my .bashrc file in Ubuntu 11.10. I think I restored it but I have two major issues now: Everything that I type has a red squiggly line under it in this field and the ...
2
votes
0answers
804 views

Why doesn't duply work when set as a cron job?

I have a problem with a cron job which starts but doesn't complete. Running the command manually works fine. I already read the page about cron issues and solutions here on AskUbuntu, tried the ...
2
votes
1answer
203 views

Script not working through Cron - JDK version mismatch between shell and script

I am executing a script through cron using the below command: */10 * * * * cd /nas/app/someFolder/psox; ./RunPSOX.sh >> /tmp/trial.log 2>&1 This is being executed by root user. All ...
11
votes
3answers
39k views

How can I tell if my hourly cron job has run?

I have created a file called ntpdate in /etc/cron.hourly #!/bin/sh /usr/sbin/ntpdate-debian date > /tmp/william_tmp date > /william_tmp date > ~/william_tmp echo test I also did Chmod 755 ...
13
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1answer
2k views

What is the story behind the default times set in /etc/crontab?

To my understanding, this is the default configuration of /etc/crontab: # m h dom mon dow user command 17 * * * * root cd / && run-parts --report /etc/cron.hourly 25 6 * * * ...
3
votes
1answer
723 views

Why does cron.hourly not care about the existence of anacron?

This question came up over in Root Access. Why does the default /etc/crontab not check for existence (and executable flag) of /usr/sbin/anacron for the hourly entry? My /etc/crontab: # m h dom mon ...
0
votes
1answer
1k views

Why isn't this simple CRON job working?

I am on Ubuntu server and would like to send an email to myself every 10 minutes (as a test). The code for that is in this file: /var/www/cron-test.php To set up the cron I typed: crontab -e ...
1
vote
2answers
734 views

Cron job fails for any time other than default * * * * *

On Ubuntu 11.10 (Oneiric Ocelot), my cron job run fine if I use the default * * * * * But if I want it to run at 17 hrs or any other time, it never runs. My settings are: 00 17 * * * wget ...
0
votes
1answer
979 views

Split a large XML file by a certain node into smaller files

I've got a XML file with 1GB (about 6000000 Lines). The goal is to split this file into smaller .xml files with more or less 20000 lines each. <?xml version="1.0" encoding="UTF-8"?> ...
2
votes
3answers
8k views

Deleting a file owned by root

Recently, a friend played a prank on my pc and now I have a file sitting on my desktop called 'hardcore_porn_xxx'. The problem is it does not go away by a simple delete. I'm new to linux so any help ...
3
votes
1answer
433 views

Good workflow for updating R modules around R-cran updates?

I like that R updates frequently to give me the best new packages, but it does seem to pose a problem for my R scripts on cron schedules. I noticed that every time ubuntu updater updates my r-base ...
0
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1answer
409 views

Cron reinstallation

Can cron be reinstalled? If so, how to take cron job backups created by system and applications like postfix, apache etc., Now after taking backups how to reinstall cron?
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1answer
2k views

In what order do cron jobs with the same schedule run?

Let's say that I have the following cron jobs: * * * * * /path/to/taskB * * * * * /path/to/taskC * * * * * /path/to/taskA Is there any guarantee to the order in which they will be run? I've seen ...
1
vote
1answer
2k views

How can I prevent two shell scripts running at the same time?

I have a tar backup script that runs once a month. It runs at night through cron. I also have a power schedule that reboots the server at 4.15 every night. The problem is that the server reboots ...
3
votes
2answers
782 views

Taking timely screenshots of particular sites

I have a website where I have to take weekly screen shots of sister sites. I was wondering how this maybe done. I had obtained the code for taking screen shots but have no idea how to open up the ...
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vote
2answers
2k views

How to get updated IP address mailed to me in DNSExit?

I'm using DNSExit on my Ubuntu server (Natty 11.04) and have installed the ipUpdate rpm file and did an apt-get install for chkconfig to enable the ipUpdate. I'd like to get an email whenever the IP ...