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I'm running a PHP script in a cronjob and I want to send emails every 5 minutes

My current (crontab) cronjob:

10 * * * * /usr/bin/php / > /dev/null 2>&1

The cronmail.php is as follows:

$from = 'D'; // sender
$subject = 'S';
$message = 'M';
$message = wordwrap($message, 70);
mail("", $subject, $message, "From: $fromn");

But I've not received an email in 30 minutes with this configuration.



In a crontab file, the fields are:

  • minute of the hour.
  • hour of the day.
  • day of the month.
  • month of the year.
  • day of the week.


10 * * * * blah

means execute blah at 10 minutes past every hour.

If you want every five minutes, use either:

*/5 * * * * blah

meaning every minute but only every fifth one, or:

0,5,10,15,20,25,30,35,40,45,50,55 * * * * blah

for older cron executables that don't understand the */x notation.

If it still seems to be not working after that, change the command to something like:

date >>/tmp/debug_cron_pax.txt

and monitor that file to ensure something's being written every five minutes. If so, there's something wrong with your PHP scripts. If not, there's something wrong with your cron daemon.

Monday, August 1, 2022

The solution you will use really depends on how long you need to wait between each execution of your function.

If you are waiting for longer than 10 minutes, I would suggest using AlarmManager.

// Some time when you want to run
Date when = new Date(System.currentTimeMillis());

try {
    Intent someIntent = new Intent(someContext, MyReceiver.class); // intent to be launched

    // Note: this could be getActivity if you want to launch an activity
    PendingIntent pendingIntent = PendingIntent.getBroadcast(
        0, // id (optional)
        someIntent, // intent to launch
        PendingIntent.FLAG_CANCEL_CURRENT // PendingIntent flag

    AlarmManager alarms = (AlarmManager) context.getSystemService(

} catch(Exception e) {

Once you have broadcasted the above Intent, you can receive your Intent by implementing a BroadcastReceiver. Note that this will need to be registered either in your application manifest or via the context.registerReceiver(receiver, intentFilter); method. For more information on BroadcastReceiver's please refer to the official documentation..

public class MyReceiver extends BroadcastReceiver {
    public void onReceive(Context context, Intent intent)
        System.out.println("MyReceiver: here!") // Do your work here

If you are waiting for shorter than 10 minutes then I would suggest using a Handler.

final Handler handler = new Handler();
final int delay = 1000; // 1000 milliseconds == 1 second

handler.postDelayed(new Runnable() {
    public void run() {
        System.out.println("myHandler: here!"); // Do your work here
        handler.postDelayed(this, delay);
}, delay);
Saturday, November 5, 2022


From the cron man page:

...cron will then examine the modification time on all crontabs and reload those which have changed. Thus cron need not be restarted whenever a crontab file is modified

But if you just want to make sure its done anyway,

sudo service cron reload


/etc/init.d/cron reload
Friday, September 30, 2022
* * * * * echo "hello" > /tmp/helloFile_$(date +%Y%m%d%H%M%S).txt

You just need to escape the parentheses.

Other date formats:

Tuesday, October 11, 2022

You're looking for cron and shell scripts.

Friday, November 25, 2022
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