The cron command

The crontab command shown below will activate the cron tasks automatically on the hour:
0 * * * * wget -O – -q -t 1 http://www.jit.co.in/cron.php

In the above sample, the 0 * * * * represents when the task should happen. The first figure represents minutes – in this case, on the “zero” minute, or top of the hour. (If the number were, say, 10, then the action would take place at 10 minutes past the hour.) The other figures represent, respectively, hour, day, month and day of the week. A * is a wildcard, meaning “every time.”

The rest of the line basically tells the server to “ping” the url http://www.jit.co.in/cron.php.
Here is a diagram of the general crontab syntax, for illustration:

# +—————- minute (0 – 59)
# | +————- hour (0 – 23)
# | | +———- day of month (1 – 31)
# | | | +——- month (1 – 12)
# | | | | +—- day of week (0 – 7) (Sunday=0 or 7)
# | | | | | * * * * * command to be executed

Add ONE of the following lines:

45 * * * * /usr/bin/lynx -source http://jit.co.in/cron.php
45 * * * * /usr/bin/wget -O – -q -t 1 http://www.jit.co.in/cron.php
45 * * * * curl –silent –compressed http://jit.co.in/cron.php.