CronSandbox
For an offline exploration of crontab expressions
Processing . . .
This opening screen is a demonstration - predefined timing values and resulting schedule.
Enter YOUR timing operators for a crontab parameter string, and click 'Run'.
You will see a list of the dates and times that your cron job would execute.
'Run' an empty box to return to the start-up demonstration values.

Reminder of the format... mm hh D M DoW
mm - the minute, a value between 0 and 59
hh - the hour, a value between 0 and 23
D - day of the month, between 1 and 31
M - month, a value between 1 and 12
DoW - day-of-the-week, 0-6 (0 = Sunday)


Each of the five items can be more complex...

A '*' means use all values.

Multiples: e.g. every 20 mins would be '0,20,40'.

Range: e.g. hourly in the evening '19-23'.

Every nth '0-23/n', '*/2' would be every other.
'*/1' is generally acceptable elsewhere, but is flagged here as possibly an unintended entry.

Month can be just the first three letters of the name,
so 'mar,jun,sep,dec' or '3,6,9,12' or '3-12/3'
would all give you quarterly reports.


The DoW can also be e.g. 'mon,wed,fri'.
It is DoW OR DoM (rather than DoW AND DoM), so e.g.
'11th OR a Tuesday' rather than '11th AND a Tuesday'.


Five items, space separated (mm hh D M DoW):

MinsHrsDayMthDoW
0523**mon,wed,fri
This run time (UTC) Sun2016-May-011151
Forward ScheduleMon2016-May-022305
Wed2016-May-042305
Fri2016-May-062305
Mon2016-May-092305
Wed2016-May-112305
Fri2016-May-132305
Mon2016-May-162305
Wed2016-May-182305
Fri2016-May-202305
Mon2016-May-232305
Wed2016-May-252305
Fri2016-May-272305
Mon2016-May-302305
Wed2016-Jun-012305
Fri2016-Jun-032305
Mon2016-Jun-062305
Wed2016-Jun-082305
Fri2016-Jun-102305

CRON-job Application

We use CRON jobs to feed our Amazon Product Image Collager web widget, a sample image is shown here.

You make your own Collage image by entering a list of Amazon product references, or start from a ready-made list of Best Sellers.

Each collage image has its own HTML Imagemap, with links to the individual product pages at Amazon.com.

Optionally, Amazon Associate IDs can be embedded into those product links. For charities registered with AmazonSmile, the links can take visitors there instead.

Your Collage image is introduced into a webpage simply by adding an HTML '<div>' tag together with a line of Javascript.

Even if you are not interested in being an Amazon Associate, a colourful graphic like this will add visitor interest to a personal site or blog.

Here is our dedicated page.