Why does my cron job run every 1 minute although I set it every 1 hour?

Question

I set my cron job via crontab -e, with the following code:

* */1 * * * python /var/www/your_script >/dev/null 2>&1

I didn't add .py extension as it makes the cron job invalid.

However, after logging it by grep CRON /var/log/syslog, the script is executed every one minute, not every one hour.

Mar  1 07:40:01 my-instance CRON[4471]: (me) CMD (python /var/www/your_script >/dev/null 2>&1)
Mar  1 07:41:01 my-instance CRON[4474]: (me) CMD (python /var/www/your_script >/dev/null 2>&1)
Mar  1 07:42:01 my-instance CRON[4477]: (me) CMD (python /var/www/your_script >/dev/null 2>&1)

Why does my script start to be run every one minute, not every one hour? My environment is Ubuntu 16.04.

Answer 1

If you want to set cronjob for every hour, you can do it any of following way:

You can run:

0 * * * * /path/to/script

which reads

On minute 0, each hour, each day of month, each month, each day of the week.

or

@hourly /path/to/script

or

0 */1 * * * /path/to/script

An asterisk (*) can be used so that every instance (every hour, every weekday, every month, etc.) of a time period is used.

Reference: crontab, CronHowto