SaltyCrane Blog

Notes on Python, Django, and web development on Ubuntu Linux

Date: 2008-09-15 | Modified: 2008-09-22 | Tags: linux, softwaretools, ubuntu | 1 Comment

Simple cron example (tested on Ubuntu):

Edit your (user) crontab file
```
$ crontab -e
```
This will bring up your editor (nano by default in Ubuntu)
Enter the following inside. This will append the current date to a log file every minute. The 6 fields of the crontab file are: minute, hour, day of month, month, day of week, command.
```
* * * * * /bin/date >> /tmp/cron_output
```
Be sure to put a newline at the end of the file.
(NOTE 1: >> only redirects STDOUT to a file. To redirect both STDOUT and STDERR, use something like /bin/date >> /tmp/cron_output 2>&1)
(NOTE 2: If output is not redirected, cron will try to email the output to you. To do this, a mail transfer agent such as sendmail or postfix must be installed.)
Exit the editor. It should output:
```
crontab: installing new crontab
```

Check that it is working:

tail -f /tmp/cron_output

You should see the date updated every minute on the minute (or close to it):

Tue Sep 16 23:58:01 PDT 2008
Tue Sep 16 23:59:01 PDT 2008
Wed Sep 17 00:00:01 PDT 2008
Wed Sep 17 00:01:01 PDT 2008
...

#1 haimeika commented on 2009-06-29:

Hi, Sofeng

I am a beginner of linux. The example is very simple but you list the steps very clearly. It is so helpful for me, and thank you very much.


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