How to Run a Cron Job at Every 5 Hour Interval

How to run a cron job every 5 hours (on Linux)

The */5 syntax means "every 5 units, starting from 0". So, if you use it in the hour position, it will match hours 0, 5, 10, 15, 20.

I'm assuming what you actually want is a strict 5 hour interval. So after hour 20, you want the next run to be at 20 + 5 hours, so at 1AM not midnight. If that's correct, there isn't an easy way to make cron work like that. It can do even intervals of all divisors of 24 though: every 2 hours, every 3 hours, every 4 hours, every 6 hours, every 12 hours.

To get the 5 hour interval, one possible workaround is to

• schedule the cron job to run every hour
• at the start of your script that the cron job runs, add extra logic to check if it should run this hour. For example, you could take the current time, and calculate the hours since epoch. And exit early unless the calculated number is divisible by 5.

How to run a cron job at every 5 hour interval

One option from this forum post on unix.com Run it every hour, and add to your script:

time_ct=$(cat /tmp/cron_time_ct)
if [ $time_ct -lt 5 ]
   then
     echo "Not yet time"
     time_ct=$((time_ct+1))
     echo $time_ct > /tmp/cron_time_ct
     exit
   else
     time_ct=0
     echo $time_ct > /tmp/cron_time_ct
fi
# rest of your task

I've done similar to do "every other monday" type logic. Running the script every monday and only allowing execution on every other one in the script.

Quartz Cron Expression for running a job every 5 hours from a given time

CronSchedule is not the best suited one for what you want to do.

Use SimpleSchedule instead:

trigger = newTrigger()
    .withIdentity("yourJobName", "yourJobGroup")
    .withSchedule(simpleSchedule()
        .withIntervalInHours(5) // every 5 hours
        .repeatForever()) // keep going in intervals of 5h
    .startAt(dateOf(12, 0, 0)) // start at 12:00 PM
    .build();

You can find more examples in the official documentation.

crontab run every 15 minutes between certain hours

Your command is fine!

To run from 7.00 until 19.45, every 15 minutes just use */15 as follows:

*/15    07-19        *     * *     /path/script
^^^^    ^^^^^

That is, the content */15 in the minutes column will do something every 15 minutes, while the second column, for hours, will do that thing on the specified range of hours.

If you want it to run until 19.00 then you have to write two lines:

*/15    07-18        *     * *     /path/script
0          19        *     * *     /path/script

You can have a full description of the command in crontab.guru: https://crontab.guru/#/15_7-19___

Run Cron job every N minutes plus offset

To run a task every 20 minutes starting at 5 past the hour, try this:

 5-59/20 * * * *

Explanation

An * in the minute field is the same as 0-59/1 where 0-59 is the range and 1 is the step. The command will run at the first minute in the range (0), then at all successive minutes that are distant from the first by step (1), until the last (59).

Which is why */20 * * * * will run at 0 minutes, 20 minutes after, and 40 minutes after -- which is the same as every 20 minutes. However, */25 * * * * will run at 0 minutes, 25 minutes after, and 50 minutes after -- which is not the same as every 25 minutes. That's why it's usually desirable to use a step value in the minute field that divides evenly into 60.

So to offset the start time, specify the range explicitly and set the first value to the amount of the offset.

Examples

5-59/20 * * * * will run at 5 minutes after, 25 minutes after, and 45 minutes after.

10-59/25 * * * * will run at 10 minutes after and 35 minutes after.

1-59/2 * * * * will run every odd minute.

How to make crontab execute every 2 hours between 10am and 10pm?

0 10/2 * * * /directory/job.sh would do it.

0 10-22/2 * * * /directory/job.sh would do it and be more explicit.

0 10,12,14,16,18,20,22 * * * /directory/job.sh would do it, too.

Run CRON job everyday at specific time

Cron utility is an effective way to schedule a routine background job at a specific time and/or day on an on-going basis.

Linux Crontab Format

MIN HOUR DOM MON DOW CMD

Example::Scheduling a Job For a Specific Time

The basic usage of cron is to execute a job in a specific time as shown below. This will execute the Full backup shell script (full-backup) on 10th June 08:30 AM.

Please note that the time field uses 24 hours format. So, for 8 AM use
8, and for 8 PM use 20.

30 08 10 06 * /home/yourname/full-backup

• 30 – 30th Minute
• 08 – 08 AM
• 10 – 10th Day
• 06 – 6th Month (June)
• *– Every day of the week

In your case, for 2.30PM,

30 14 * * * YOURCMD

1. 30 – 30th Minute
2. 14 – 2PM
3. *– Every day
4. *– Every month
5. *– Every day of the week

To know more about cron, visit this website.

How to setup cron job to run every 5 days?

0 0 */5 * *  midnight every 5 days.

See this, similar question just asked for every 3 days.
Cron job every three days

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