Using crontab to execute script every minute and another every 24 hours [closed]

Question

I need a crontab syntax which should execute a specific PHP script /var/www/html/a.php every minute. The execution on every minute must start at 00:00. The other task which must execute a script at 00:00 /var/www/html/reset.php (once every 24 hours).

Answer 1

every minute:

* * * * * /path/to/php /var/www/html/a.php

every 24hours (every midnight):

0 0 * * * /path/to/php /var/www/html/reset.php

See this reference for how crontab works: http://adminschoice.com/crontab-quick-reference, and this handy tool to build cron jobx: http://www.htmlbasix.com/crontab.shtml

Answer 2

This is the format of /etc/crontab:

# .---------------- minute (0 - 59) # |  .------------- hour (0 - 23) # |  |  .---------- day of month (1 - 31) # |  |  |  .------- month (1 - 12) OR jan,feb,mar,apr ... # |  |  |  |  .---- day of week (0 - 6) (Sunday=0 or 7) OR sun,mon,tue,wed,thu,fri,sat # |  |  |  |  | # *  *  *  *  * user-name  command to be executed 

I recommend copy & pasting that into the top of your crontab file so that you always have the reference handy. RedHat systems are setup that way by default.

To run something every minute:

* * * * * username /var/www/html/a.php 

To run something at midnight of every day:

0 0 * * * username /var/www/html/reset.php 

You can either include /usr/bin/php in the command to run, or you can make the php scripts directly executable:

chmod +x file.php 

Start your php file with a shebang so that your shell knows which interpreter to use:

#!/usr/bin/php <?php // your code here