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

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Is there any reason this cronjob would fail in cron, but not on the command line?

I have written a little one liner that will email me when a list of files changes - I used sha512 to generate a list of hashes and then periodically check that those hashes still match. */5 * * ...
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2answers
1k 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 that,...
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157 views

How to run browser in background in Ubuntu

I am using Ubuntu 14.04, and PHP. I have 2 files: test.html - content java to test network update.php - the test file will post result to update database. I need to run and execute an URL address ...
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1answer
112 views

btrfs won't run from cron

I'm trying to set up a cron job to create a btrfs subvolume snapshot of my root partition. The command works perfectly if I run it from the command line, but nothing happens at the scheduled cron time....
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1answer
2k views

DD-WRT Additional Cron Jobs aren't running

I have installed DD-WRT (v24-sp2 (06/23/14) std - build 24461) on a TP-Link TL-WR841ND v9 and I'm trying to add a CRON job to update my Unlocator IP configuration as described here: How to set up a ...
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273 views

crontab is not working

I am using Linux Fedora. I want to create a crontab with SCP command, but it's not working. [shiv@db2 ~]$ crontab -l #this is server to server copy... */2 * * * * date >> ~/$ scp shiv@127.0.0.1:...
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4answers
702 views

How to use “date” to print tomorrow's day of the week

On CentOS 6 Linux I use date +%a in several cronjobs and scripts to generate logfile names like myprog-Tue.txt and this works well for me since many years. But now for one program I need to delete ...
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245 views

Is there a way to tell cron to trigger a particular cron job right now?

The cron job for updatedb didn't run because the system was powered off at the time. I'd like to tell cron to run that job now, as if now were the schedule time. Is there a way to do that? For this ...
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3answers
714 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 < $...
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20 views

How can I queue a script to run the next time a system is up and connected to the internet?

I'm using mailsend (on a Mac) to send mail from the command line. I'd like to set this up such that I can execute a send command, but if my system is disconnected from the internet, that command is ...
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54 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 ...
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1answer
428 views

mysql backup verification

Im not a dabase admin or advanced database user or advanced linux user.. but I would like to know how to verify mysql dumps because I am backing up my own sites manually. Normally when backing up lot ...
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1answer
421 views

Ubuntu Cron ec2-create-snapshot

I have a new ec2 Ubuntu instance running. I have properly set up the ec2-api tools. I want to create a daily backup using the ec2-create-snapshot command. Just to test it, I have my script, which is ...
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35 views

How can I run a cron job from PM to AM? [duplicate]

I want to execute a script once an hour from 20:00 to 08:00. Would the following work? 0 20-8 * * * location_of_script_to_run I'm currently using the following: 0 20,21,22,23,0,1,2,3,4,5,6,7,8 * * ...
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224 views

cron job monitoring script

greeting of the day!!! please help me a situation, i am trying to develop a script which provides me details which my cron job is commented or stopped which job is running or scheduled. like we ...
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2answers
125 views

How can I get a script to run constantly on Mac OS X?

I would like to do this: When the application VLC is open and I press the space bar, it pauses the video and an itunes starts to play. Then spacebar again would resume the workout video and pause my ...
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1answer
95 views

Set cron's maximum run counter

How do I setup cron to run only for a specific number of times? Let's say I want to setup cron so that it runs hourly, but when the scheduler has already run five times, I want to stop cron. How do I ...
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1answer
569 views

WGET/cron downloading webcamera file

our new town doctor put a web camera to his waiting room for people to see how much crowded it is. As my mom and grandparents go to this doctor, I wanted to download the files periodically and if they ...
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1answer
527 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 ...
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1answer
2k views

Cron error “missing url”

Hope this is the correct place to post this. I am setting up a cron job to refresh a twitter feed. I want to overwrite the file each time the cron job executes. My current command is: /usr/bin/wget -...
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1answer
1k views

Simple script run via cronjob doesn't work but works from shell

I am on shared hosting and I'm trying to schedule cronjob to run every now and then. Via cPanel I scheduled to execute my script but even though that according to my host support the cronjob runs, the ...
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2answers
109 views

What is the risk when editing crontab file without the “crontab -e” command?

I developed a script in which I add lines to the crontab file with echo command and I remove lines with sed command. I do not know the risk of that especially that I find in some web site that we ...
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1answer
79 views

Run cron task at specified day of week but at any time

I ran into trouble with cron. I need to run task on my desktop but the thing is I can't guarantee that my computer will be turned on in specified time. For example I need to execute task weakly If ...
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1answer
115 views

Script not running as cronjob

I got a script which runs in a cronjob as root. The problem is that the addgroup command would output "Command not found" when it gets executed by the script. #!/usr/bin/perl $datei = `ls /var/www/...
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1answer
107 views

Check shell Script copy Status

I have a cron script and i need to adjust it; Actually some clients are generating in a directory some files, my task is to backup that files to a tape, and i need to make a if then else cp $files $...
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1answer
396 views

Have cron parse SSH config file for server addresses and options

How does one configure cron to parse ~/.ssh/config to get the IP addresses and other options (such as IdentityFile) for SSH? Obviously adding source /home/user/.ssh/config does not help. I do not ...
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1answer
84 views

Back up (save) the same file at periodic intervals

I am saving a stream in my HDD. I'd like to copy the file periodically into a subfolder backup such that the older versions of the the file are not deleted. Simply put Assume the original file is ...
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571 views

How to Schedule Tasks according to several Timezones

I need to use Windows Scheduler or any other app for setting jobs at a concrete time depending on destination country. That means scheduling a job at 7 am (UK Timezone), another at 7 am (US Timezone),...
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1answer
171 views

How to run a launchd task every weekend once?

I am trying to run a ruby program as a cron. I have figured out how to run the ruby program from a launchd The problem is that I don't know how to say "Run the job once every Sunday". Below is my ....
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1answer
544 views

Shell script not running with cronjob

I am using PUTTY to reach the server. I can dump the databases with the following command: /usr/bin/mysqldump --all-databases | /bin/gzip > Backup_DB/alldatabases_test.sql.gz When I am running ...
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1answer
426 views

Tracking down edits to my /etc/hosts file

Every hour at :49, my hosts file is being replaced with the following: # Copyright (c) 1993-1999 Microsoft Corp. # # This is a sample HOSTS file used by Microsoft TCP/IP for Windows. # # This file ...
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1answer
180 views

Cronjob immediately shuts down mac after boot

I was messing around with cronjob trying to get it to forcibly shut down at a certain time everyday, but now I can't keep my computer on. It boots, loads whatever needs to load on startup, then ...
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2answers
242 views

Automated apt-get upgrade quits midway

I set root's cron to automatically run apt-get upgrade. Easy enough. Here's the specific line: @daily (apt-get update && apt-get -y upgrade) 2>&1 > /var/log/tmp.log However, I've ...
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2answers
80 views

User-friendly wrapper or replacement for `at` command under OS X

I often want my computer to automatically add something to my to-do list at some point in the future. In some cases I want to add the same thing at regular intervals. In these cases I use OS X's ...
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1answer
471 views

Shell script truncated when run from cron or at

I'm seeing some very strange behavior on a Linux based NAS (DNS-323) I have. I'm using a simple shell script to back up the files on the NAS to another box. After making some recent additions, the ...
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1answer
2k views

Can postfix forward all outbound email to a relayhost except for local user-to-user email?

On my home Ubuntu box, postfix is configured to relay all outgoing email to outgoing.verizon.net. Unfortunately this includes local user-to-user email (e.g., from local cron jobs to me, or from me to ...
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1answer
151 views

Use of crontab, kill and trap

I'm learning crontab command, and I'm doing some tries. I edited the default crontab file with the command crontab -e, and I want to put a line that every minute send a SIGUSR1 to the current shell ...
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1answer
474 views

Editing IPTABLES nat rule in cron job

I am sitting here with an issue: I need to switch the source interface for iptables' NAT rule at a given time. I want to basically do soemthing like this - caution: concept code: #!/bin/bash if [ it ...
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1answer
615 views

Who starts updatedb process and why it uses 700+% CPU?

I have a VPS running CentOS, and recently its CPU usage goes over 700% for two times already. It always turns out to be a process named "updatedb" (as show in the figure below). After a quick ...
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1answer
299 views

How to update CRL automatically?

I have the following issue: I have a self-signed CA (certificate authority) mainly for persoanl use (mail encryption and signing, ...). I created several ceertificates and the CRLs (which are empty ...
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3answers
157 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 ...
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1answer
53 views

Why is this cron sometimes activing daily and sometimes every three days? (which it's intended to)

I have a line in my crontab like this: 01 6 * * */3 $TASK The variable $TASK emails me a particular email. I understand that I have written the cron to trigger this action at 06:01am every third ...
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1answer
497 views

How can I run a Cygwin command (not a Windows native command) as privileged?

If I open a (elevated via UAC) Bash Shell in CygWin: Luis@Kenobi /cygdrive/c/Windows/system32 $ crontab.exe -l -u Luisito must be privileged to use -u Tested on WinXP-SP3 and Win7-SP1. Same results ...
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1answer
331 views

How can I select what user account will run a Windows service (run as) from command-line?

As one of the steps for installing CRON daemon for CygWin in Windows, it is worthful (not mandatory on WinXP, but seems to be greatly adviced since Win7) to change (along with some others ...
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3answers
5k views

Why does this script fail when run from cron, but works when run manually?

I have a relatively simple bash script that works great when invoked directly, but fails when run by cron. Why does this fail and how can I make it work via cron? #!/bin/bash apt-get update -y apt-...
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1answer
115 views

What permissions do I need to give my user to run “shutdown -r 5” command from cron?

I’m have a bash script that I run in /etc/crontab on Linux $ uname -a Linux mymachine.com 3.4.76-65.111.amzn1.x86_64 #1 SMP Tue Jan 14 21:06:49 UTC 2014 x86_64 x86_64 x86_64 GNU/Linux The bash ...
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0answers
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Running cron on Cygwin to call notifu

I have installed Cygwin with cygrunsrv and Cron so I could use the benefits of using Linux-style scheduling in Windows. I want to call notifu from a cron job. I Installed cron as a service using the ...
2
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2answers
811 views

How do you use the run-parts command?

For some reason my crontab is not running the hourly/weekly/etc scripts. It seems to be that run-parts is not working and I cant get it to work on my local machine as well. Is there a mistake in the ...
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2answers
272 views

Using cron vs. system managed service for frequent tasks

If some task should run in an frequent but not neccessary precise manner, what would the benefits of using cron vs. just using a service (eg. managed by upstart) with a loop script like #!/bin/sh ...
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63 views

Cron deamon written in shell

I'm looking for a script in bash or ksh, that would do ... more or less ... the same as crond. The situation is, that our system administrator suddenly denied the use of crontab to all regular users (...