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

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4
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1answer
75 views

Is it possible to put arithmetic expressions in a crontab?

I know I can do simple arithmetic in shell scripts, like so: #!/bin/bash ((sum = 1 + 2)) echo sum This will output 3 on execution. My question now is, can this kind of expressions be used in ...
-2
votes
1answer
127 views

How to send a message in Minecraft before rebooting the server? [duplicate]

I have a Ubuntu Linux Server 14.04 LTS which is running a Minecraft server. I want it to reboot every 6 hours. I have that now and after the reboot, it starts the Minecraft server. Now what I want. I ...
0
votes
1answer
86 views

Autodelete old files

I've many shares on my samba server with recycle bin module activated. When deleting remote files from Windows I see .Trash directory. I'd like to automatically remove older files, i.e. 30 days or ...
1
vote
1answer
269 views

Add a custom CRON job from the command line?

Debian seems to have directories for cron jobs such as /etc/cron.daily and /etc/cron.hourly, but is there a way for me to automate editing, removing, and updating cron jobs from an automated script? ...
2
votes
3answers
83 views

Limit a text file to 100MB

I have several log files on my server that I would like to limit to 100MB large. I'm considering creating a cron job that will run once a month and remove the oldest characters (closest to the top) ...
2
votes
0answers
533 views

`crontab -e` sometimes fails with “Creation of temporary crontab file failed”

From time to time crontab -e fails on me on a Ubuntu box. It is the same for all users including the root and crontab -eu <user> under the root. Goes like this on a regular basis, a success here ...
1
vote
1answer
48 views

Insert variable and keep the variable

I'm on VMWare which, no matter what anyone says, responds to most unix commands. Some things are unique though, for example the fact that almost no files are persistent through reboot. Due to this ...
9
votes
1answer
213 views

Finding which cron jobs are scheduled to run at some future date/time X

Is there a way to "query" a crontab to find which cron jobs run at some arbitrary date/time, or during a certain range of times? For example, determine which will be run at sometime between 14:00 and ...
0
votes
1answer
106 views

don't log cron events in auth.log

In my /etc/rsyslog.conf, I have following line to log auth facility into /var/log/auth.log: auth,authpriv.* /var/log/auth.log but the file is flooded with cron logs, sucgh as these: ...
0
votes
2answers
70 views

Write log for a false statement of an if condition which returns exit 2

I have a script running every 5 mins with two exits in a condition clause. #!/bin/bash date=$(date +%Y) if [ $date -eq '2014' ] then echo "Current year is $date" exit 0 else echo "Current ...
1
vote
2answers
1k views

Script runs manually but not from cron

As per the monitoring of my mysql replication status. I wrote a simple shell script with the following code #!/bin/bash date > /tmp/mysql_repl_status.txt cd /usr/bin/ "/usr/bin/mysql" "-e" "SHOW ...
2
votes
1answer
229 views

where does Cron look for the default mail binary?

I have setup Cron Jobs to run inside a Chroot Environment, depending on the User/Group; I have noticed that these cron jobs, running inside the chroot environment, fail to send any mail. Log files ...
4
votes
2answers
285 views

Execution order with multiple commands

I'm relatively new to Linux and I'm working on a CronTab for scheduled backups. I figured out how to do multiple sequential jobs with ; and &&, but I'm unsure how the dependency affects the ...
1
vote
1answer
304 views

Crontab does not run?

crontab -e 0 */4 * * * root /usr/bin/rsnapshot hourly 30 3 * * * root /usr/bin/rsnapshot daily 0 3 * * 1 root /usr/bin/rsnapshot weekly 30 2 1 * * root /usr/bin/rsnapshot monthly tail ...
1
vote
2answers
114 views

Where is the cron information stored on my gentoo system?

I have a Linux gentoo system, which performs a cronjob every day at 3:10 in the morning. However, no file in /etc contains any related information to this particular cronjob, and the result of crontab ...
5
votes
2answers
17k views

Cron job to delete files older than 3 days

I need to remove files older than 3 days with a cron job in 3 different directories. (these 3 directories are children of a parent directory /a/b/c/1 & /a/b/c/2 & /a/b/c/3) Can this be done ...
7
votes
1answer
3k views

Recover cron jobs accidently removed with crontab -r

I entered crontab -r instead of crontab -e and all my cron jobs have been removed. What is the best way (or is there one) to recover those jobs?
3
votes
3answers
203 views

Detecting cron tasks run by another user

I am currently working through the Nebula challenges on exploit-exercises.com, and one of the challenges relies on a script being run by cron. This is run by another user (flag03) and the user I am ...
2
votes
1answer
224 views

How do I set cron to run on background?

I am on ubuntu 12.04 and following this tutorial. I want to setup cron to run in the background but I don't have a chckconfig in sbin so I can't run sudo /sbin/chkconfig crond on I am fairly new to ...
30
votes
1answer
1k views

Why aren't crontabs stored in user home directories?

I'm curious to know: why are crontabs stored in /var rather than in the user's home directories? It makes it a total pain to isolate these files for upgrades but I suspect that there is a logical ...
-1
votes
1answer
120 views

Cron spamming because of renice [closed]

I have a bash script that I execute using cron. The script begins like this: #! /bin/bash DIR=/home/pi/bin/run renice 19 -p $$ ionice -c 3 -p $$ : Now, every time cron runs this script it sends ...
1
vote
1answer
250 views

Shell script and crontab to capture file size, name and date in a CSV file and then send via email?

I have a number of zip files in a certain folder. I want to capture file name and the size of the files in a CSV format in day wise and put it in crontab so I can report on a daily basis, and then ...
2
votes
1answer
202 views

Logrotate behaving unexpectedly

Find below the logrotate configuration that I'm using /usr/local/nagios/var/nagios.log { copytruncate daily rotate 7 compress missingok size 100M } And I could notice that ...
2
votes
1answer
54 views

XML command line tool postgres

I have an XML files to read and load into database daily at night (cron) So i planed to do this in a batch. Is there any command line tool to : 1. Create a postgres schema using an XSD file? 2. ...
4
votes
1answer
1k views

Automatically detect when a file has reached a size limit

I would like to send an email when a file reach a certain size limit. The only way I thought of doing this is by doing a cronjob which will check the file size and send the email if the file is ...
0
votes
0answers
328 views

Using gpg-agent to decrypt password in cron job

I have two scripts that both need to decrypt passwords using gpg-agent. Both of them run fine when launched from the terminal. The problem is that when run via cron, they both fail with these ...
0
votes
2answers
5k views

Run a script at startup

I am using Ubuntu 14.04. I wrote a small script named trial. The contents of the script are as follows: #!/bin/sh SHELL=/bin/sh PATH=/bin:/sbin:/usr/bin:/usr/sbin sh -c firefox I copied the ...
3
votes
1answer
296 views

Crontab suspicious activity

I tried using crontab -l from my terminal as root, it showed no crontab for root. So I tried crontab -e, it returns the following no crontab for root - using an empty one 888 and then the ...
1
vote
1answer
777 views

debian7 cron.allow & cron.deny files

Almost 3 weeks that, in my downtime, I try to find out where the files cron.allow & cron.deny are located in debian7 distro. No way, it seems that by default they are not in the system. 'Just' ...
0
votes
0answers
97 views

Fetching all Git repositories in the background

I'm thinking about setting up a cronjob for fetching all my repositories every once in a while, to have the current status ready in case I'm offline. Something like the following (wrapped for better ...
5
votes
1answer
345 views

BASH_ENV and cron jobs

I have several questions related to non-interactive, non-login shells and cron jobs. Q1. I have read that non-interactive, non-login shells only "load" $BASH_ENV. What does this exactly mean? Does ...
1
vote
0answers
108 views

Cron job running but not establishing tunnel

I have a script which establishes a reverse tunnel on an endpoint HostB. It looks like this: cat tun.sh #!/usr/bin/env bash # Test code /usr/bin/ssh -V 1> /home/userA/bin/tun.stdout 2> ...
0
votes
1answer
211 views

How to force crontab to check for changed files

I have a gentoo Linux system in which I am logged in as root. How can I force crontab to read new/changed files in /etc/cron.d immedeately, so that even a new cronjob is executed if even only seconds ...
3
votes
2answers
766 views

crontab exclude specific date only

How can I write a cron that will exclude a specific date. let say : I need to run a crontab 6pm to 9pm in every 30 min on weekends and want to exclude 10th may 2014 only. Is It possible? How can I ...
6
votes
3answers
22k views

How do I find out why cron is not running my jobs?

I'm using Ubuntu 14.04, and the cron daemon is running: # ps ax | grep cron 822 ? Ss 0:00 cron but it is not executing any jobs. I was previously getting entries in /var/log/syslog such ...
1
vote
2answers
51 views

cronjob time 13 * * * *

It surely going to sound like a silly question but i wanted to have a confirm about that crontab time 13 * * * * does it really mean to launch at the 13th minute of every hr of every day of every ...
1
vote
0answers
160 views

Incrontab does not execute command

When I use incrontab out of the box, I mean no changes, I get no result, as if the command was not executed. my incron line is : /crrae IN_CREATE,IN_CLOSE_WRITE,IN_MOVED_TO /usr/bin/unix2dos $# the ...
2
votes
1answer
38 views

Conflict between cron.deny and allow who wins?

which one wins in conflict deny or allow? Is the behavior the same for hosts.allow and all the other similar files?
6
votes
2answers
2k views

System Crontab or Root Crontab

System crontab: /etc/crontab Root crontab: sudo crontab -u root -e Which way is preferred? As they all run tasks within administration privilege.
3
votes
2answers
2k views

Automating backups run from a bash script in Linux the right way

I have a bash script I wrote to backup a Moodle installation. It works fine, I've tested the backups, but there's a problem with it; when I do the backups, since I have to use sudo to type the ...
2
votes
1answer
2k views

Executing PHP with CronJobs in CentOS 6.4 not working?

So I've spent around 2-3 hours now and some times researching, I found several of the same responses online but none seem to work! I'm trying to execute a PHP script every minute (as a test), but it ...
-1
votes
1answer
635 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
votes
4answers
967 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
vote
2answers
264 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
vote
0answers
29 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
votes
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 ...
0
votes
0answers
2k 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
vote
1answer
320 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
votes
1answer
618 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
vote
1answer
683 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 ...