Cron, Cron job, Cron script, Crontab

Apa itu cron, cron job, cron script, crontab

cron is a Unix command for scheduling one or more commands (collectively called a cron script or cron job) to be automatically executed on the computer at a specified time(s), usually periodically, such as emailing daily reports.  

Cron is a daemon process, which means it runs continuously in the background, waiting to run a specified operation at predefined times or when specific events occur.  

crontab is a Unix command that creates or modifies a file (called a crontab file) that contains a cron table (cron tab) or list of Unix shell commands, each having a specified time of execution by the operating system.
From website: http://www.free-webhosts.com/definition/cron.php

command yg digunakan untuk cron

crontab –l = list semua cron

crontab –e = untuk edit cron

crontab –r = remove semua cron user

(esc) :q! =  keluar tanpa save

(esc) :wq! = save n keluar

! = guna utk force.

Kalau guna keyboard, jangan sekali-kali guna number disebalah kanan.

Kalau file format .php path depannya /usr/local/bin/php

eg:  00     13     *      *     *     /usr/local/bin/php /usr/home/abc/xyz/listCo.php 

Kalau file format .sh path kat depan /usr/local/bin/bash

eg: 00     13     *     *     *     /usr/local/bin/bash /usr/home/abc/xyz/listCo.sh

Lepas tu bagi full path dekat mana file tu berada termasuk nama file sekali.

eg: /usr/home/abc/xyz/listCo.sh

Bawah ni example utk buat cron berdasarkan waktu.

Field	1	2	3	4	5	6
Function	Minute	Hour	Day of month	Month of year	Day of week	Command
Ranges	0-59	0-23	1-31	1-12	0-6 Begins with Sunday (0) and ends Saturday (6).

00            13            *           *             *            /usr/local/bin/php /usr/home/abc/xyz/listCo.php 

(1pm setiap hari)

00           */2          *            *            *            /usr/local/bin/php /usr/home/abc/xyzt/listCo.php

(setiap 2 jam)

*/30       *             *             *             *             /usr/local/bin/php /usr/home/abc/xyzt/listCo.php

(setiap 30minit)

00           01           3              *             *             /usr/local/bin/php /usr/home/abc/xyz/listCo.php

(1am hari ke-3 setiap bulan)

00           01           *             *            1-5           /usr/local/bin/php /usr/home/abc/xyz/listCo.php

(1am setiap hari isnin-jumaat)

00           01           *             5              *             /usr/local/bin/php /usr/home/abc/xyz/listCo.php

(1am setaip hari dalam bulan 5 sahaja)

00           01           3              6              *             /usr/local/bin/php /usr/home/abc/xyz/listCo.php

(1am hari ke-3 dalam bulan 6 sahaja)

00           01           *             8              5-6          /usr/local/bin/php /usr/home/abc/xyz/listCo.php

(1am setiap Jumaat dan Sabtu dalam bulan 8 sahaja)

p/s: Kalau salah info bgtau yer.

RC: Semua benda klu boleh aku nak cronkan. Kalau boleh la. masalanya tak boleh.. waaa...