Cron linux log file

Ubuntu Create a cron.log File To Log crontab Logs [16.04/18.04/20.04]

Defaults

Type the following command to view default entries:
$ sudo tail -f /var/log/syslog
OR better use the grep command to find cron job in that file:
$ sudo grep -i cron /var/log/syslog
Sample outputs:

Fig.01: Ubuntu Linux: Where is my crontab log file?

Use systemctl command to view cron logs

You can also use the following command to just see latest CRON task related entries on Ubuntu v16.04 LTS+ only:
$ sudo systemctl status cron

Use journalctl command to display log

Type the following command to see cron logs on Ubuntu v16.04 LTS+ only:
$ sudo journalctl -u cron
$ sudo journalctl -u cron -b | more
$ sudo journalctl -u cron -b | grep something
$ sudo journalctl -u cron -b | grep -i error
Sample outputs:

• -u cron : Show messages for the specified systemd unit UNIT called cron
• -b : Show messages from a specific boot i.e. from the beginning of the journal.

How to enable or create a cron.log file to contain just the CRON entries

Edit the /etc/rsyslog.d/50-default.conf file, enter:
$ sudo vi /etc/rsyslog.d/50-default.conf
### or use a nano text editor ###
$ sudo nano /etc/rsyslog.d/50-default.conf
Find the line:

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Comment out (uncomment line) in a configuration file as follows:

Save and close the file. Restart rsyslog service, enter:
$ sudo systemctl restart rsyslog
## verify it ##
$ sudo systemctl status rsyslog
Sample outputs:

You can now see cron log entries in /var/log/cron.log file:
$ sudo tail -f /var/log/cron.log
$ sudo grep something /var/log/cron.log
Sample outputs:

Conclusion

You learned how to create a cron.log file on Ubuntu Linux server.

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How to Check Cron Logs on Ubuntu 18.04

In this tutorial, we’ll look at how to check cron logs and monitor jobs in real time in Ubuntu 18.04. A cron job is a task scheduler used for automation of repetitive tasks in a Linux environment. It is normally executed at a specific time and date as dictated by the system administrator. Cron logs really help admin to verify if the cron jobs have run or not at the particular time.

Usually, you can view cron events using

Output

However, it’s more preferable to have a separate cron.log file which you can use to monitor cron events.

Setting up cron.log file

First off go to /etc/rsyslog.d/50-default.conf file and search for this line #cron.* /var/log/cron.log

Output

Using your favorite text editor, open the file and uncomment the line as shown in line 10

Next, create cron.log file

Restart the rsyslog service

Check the status of rsyslog to ensure it is running

Sample Output

From then henceforth all log will be saved at /var/log/cron.log file.

Next, we are going to create a watchcron command which we will invoke to have a glimpse at the cron events in real time.

create the watchcron file

Add the following

Note :

watch -n 10 refreshes the page every 10 seconds.

tail -n 25 displays the last 25 entries.

Give the watchcron file execute permissions

Copy it to /usr/sbin as shown

To watch real-time cron events run

Sample Output

If you don’t wish to receive emails from cron, append this line at the beginning of your crontab file

In this article, we have shown you how to monitor cron jobs logs in real time using a single command. Feel free to try out the procedure and give us your feedback. Thank you.

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Ubuntu Linux check cron log file error or messages in /var/log/cron.log file

Is crond (cron server) running?

Use the pgrep or ps command as follows to verify that crond is running:

Fig.01: Is cron service running on Debian or Ubuntu Linux?

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Where are cron logs stored on Ubuntu Linux?

The logs are stored in /var/log/cron.log file. You need to configured it as follows. Edit /etc/rsyslog.d/50-default.conf file using a text editor such as vi or nano:
$ sudo vi /etc/rsyslog.d/50-default.conf
OR
$ sudo nano /etc/rsyslog.d/50-default.conf
Find the line:

Uncoment the line (i.e. remove # ):

Restart the following two services:
$ sudo service rsyslog restart
$ sudo service cron restart
Sample outputs:

Now, where are cron errors logged in Ubuntu LTS server?

You need to view /var/log/cron.log file using the grep or tail command:
$ sudo grep something /var/log/cron.log
$ sudo more /var/log/cron.log
$ sudo tail -f /var/log/cron.log
$ sudo egrep -i ‘error|log’ /var/log/cron.log
$ sudo tail -F /var/log/cron.log
Sample outputs from my log file:

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Где находится журнал cron / crontab?

Я хочу убедиться, что моя работа cron выполняется и в какое время. Я считаю, что есть журнал для моей sudo crontab -e работы, но где?

Я искал в Google и нашел рекомендации для поиска /var/log (в котором я ничего не вижу с «cron» в названии) и для редактирования файла, /etc/syslog.conf которого у меня тоже нет.

При установке по умолчанию задания cron регистрируются в

Вы можете увидеть только задания cron в этом лог-файле, запустив

Если вы ничего не перенастроили, записи будут там.

Вы можете создать файл cron.log, содержащий только записи CRON, которые отображаются в системном журнале. Обратите внимание, что задания CRON по-прежнему будут отображаться в системном журнале, если вы будете следовать следующим указаниям.

Найдите строку, которая начинается с:

раскомментируйте эту строку, сохраните файл и перезапустите rsyslog:

Теперь вы должны увидеть файл журнала cron:

Активность Cron теперь будет регистрироваться в этом файле (в дополнение к syslog).

Обратите внимание, что в cron.log вы увидите записи о том, когда cron запускал скрипты в /etc/cron.hourly, cron.daily и т. Д. — например, что-то вроде:

Однако вы не увидите больше информации о том, какие сценарии фактически выполнялись внутри /etc/cron.daily или /etc/cron.hourly, если только эти сценарии не направляют вывод в cron.log (или, возможно, в какой-либо другой файл журнала).

Если вы хотите проверить, работает ли crontab и не нужно искать его в cron.log или syslog, создайте crontab, который перенаправляет вывод в файл журнала по вашему выбору — что-то вроде:

Это перенаправит все стандартные выходные данные и ошибки, которые могут возникнуть в сценарии, который выполняется, в указанный файл журнала.

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How to check cron logs in Linux

We will discuss in this article how a user can view the cron logs files in a Linux environment. We have performed all tasks on the Ubuntu 20.04 system that will give you a better understanding of the cron logs.

Open the terminal by pressing the keyboard shortcut ‘Ctrl+Alt+t’. Now, using the following two different methods can easily access the cron log events:

Method 1: Check cron logs events through syslog

It is a very simple and easy way to check that cron log events are running on your system. Login as root user on the terminal and type the following command:

The following cron logs events should display on the terminal:

Method 2: Monitor cron logs by setting up the cron.log file

The recommended way is to create a separate ‘cron.log’ file to monitor or check the cron logs events on your Linux system. For this purpose, access the ‘/etc/rsyslog.d/50-default.conf’ file by running the below-given command:

Search the ‘ #cron.* /var/log/cron.log’ in this file and uncomment this line which is also shown in the following screenshot:

Now, create a ‘cron.log’ by using any source code or text editor.

Restart the rsyslog service and then check the running status of this service on your system through the following command:

$ sudo systemctl restart rsyslog

$ sudo systemctl status rsyslog

The following output should print on the terminal window:

Now, all cron log events to be saved in the cron.log file.

To view, the real-time cron logs events using the ‘watchcron’ command. So, create a ‘watchcron’ file as follows:

Add the following lines in this file:

watch -n 10 tail -n 25 / var / log / cron.log

Save this file in nano using ‘Ctrl+o’ and then press ‘Ctrl+x’ to exit from this environment.

Here, the above watchcron refreshes the logs event page after 10 seconds and displays the last 25 events on the page.

Set the executable permissions on this file by using the following command:

Copy this file in ‘/usr/sbin’ location as follows:

Now, to check the real-time cron logs events run the below-given command on the terminal:

The following window will show on the terminal:

Conclusion

We have explained In this article how you can check or monitor cron logs events in real-time by using a single ‘watchcron’ command.

About the author

Karim Buzdar

Karim Buzdar holds a degree in telecommunication engineering and holds several sysadmin certifications. As an IT engineer and technical author, he writes for various web sites. He blogs at LinuxWays.

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