How to cron a script

djumaka

Hi,
I got the following problem:
How to cron a script to run every 1hour or so and do some job.

Tell me how to cron a script at all.

TIA,
Boyan Djumakov

sasito

To use cron, you must first set up a file of cron entries. This file can
actually be placed anywhere in your account you like, and have any name
you want. It should contain one entry for each action you want taken.

A cron entry looks similar to the following:

30 3 * /usr/bin/nice -20 /usr/home/username/script.php

In this case, the script "script.php" would be run nightly at 3:30 AM.
Between the fifth digit and the "/usr/bin/nice" we recommend putting a
literal "tab" character.

"/usr/bin/nice -20" utilizes the system nice command to lower the impact
of the call on the server.

PLEASE NOTE IN ORDER TO RUN A PHP CRON SCRIPT YOU NEED PHP TO BE INSTALLED LIKE STAND ALONE MODULE, NOT LIKE APACHE MODULE.

"/usr/home/username/script.php" is the full path to the script/program you
would like cron to run. You can also use regular UNIX commands here if
you like, using full paths to programs. For instance, you could have

30 3 /usr/bin/nice -20 /bin/rm /usr/home/username/temp/

to remove all files from some temporary directory you might have each
night at 3:30 AM, as in the earlier example.

The "30 3 *" requires a bit more explaining. The time a cron command
is executed is controlled by the 5 numbers that precede the cron
directive.

The first number is the minutes after the hour (0-59).
The second is the hour of the day (0-23, with 0 being 12 AM).
The third number is the day of the month (1-31).
The fourth is the month of the year (1-12).
The fifth is the day of the week (0-6, with 0=Sunday and 6=Saturday, etc).
A in place of any of the values matches all possibilities (for
instance, in the given example the script runs every day because the 's
for day of the month, day of the week, and month of the year match all
values).

Multiple values are separated by commas. For instance, you might start
with 15 1,3,5 * to run a script every day at 1:15, 3:15, and 5:15.

Once you have your cron directive file (say, cron.file) in your account,
you must connect via telnet and issue the command

crontab cron.file

using the name you gave the file. (Note that you must be in the same
directory as the cron file at the time.) After this, your cron should be
activated. If the programs running via cron generate errors, the cron
daemon will e-mail them to your account. If at any time you would like to
change your cron jobs, just edit your file, and rerun the crontab command
as shown above.

Sincerely.

SaS.

Anon

Not so long time ago I asked here the same question and this forum helped me to do it, so, I will try to explain, and any questions are welcome :-)
So, at first you should write PHP script, which you want to cron, of course :-)
Then you go to UNIX and edit crontab. If you're familiar with VI editor, the next step is not for you, but for me VI is a headache. So, on bash you write:
export EDITOR=pico

Now you can edit CRON in PICO.
To insert your job into CRON you should edit CRONTAB, with command:

crontab -e

Each line of this file is a job. So, to insert your job, you should create a new line. It has special format, for example:

00,30 12,13 5 * 0 /usr/local/bin/wget http://www.your_url.com/parse/parse.php3

So:
00,30 - the minutes when to run your job (here at :0 and :30 minutes both);

12,13 - hours (0-23 hours), so now you understand that our script will run at 12:00, 12:30, 13:00, 13:30;

5 - day of month.

- month (* for any, for ceratin month you use numbers 1-12, of course);

0 - day of week (0-6, 0 is Sunday).

"/usr/local/bin/wget" is path to WGET on my server. They told I could use LYNX for the same prupose but I could not get it working, so I used WGET to start my script.

And the last parameter is, of course, URL of your script.

jc94062

I struggled for ages to do this, then contacted my host, two hours later I got a reply, 10 minutes later I had it working 🙂

here what he told me (running a db cleaning sweep twice a month, 15th and 30th)

00 00 15,30 /usr/local/bin/php /your/path/to/phpscript

Works fine 🙂

Anon

To contact host is really good idea :-)

Anon

I'll add a couple of other things you might find conusing.

First, be sure to compile PHP into a stand-alone executable first (i.e. into cgi mode). Since most of us run PHP as an apache module, you'll probably need to compile it twice. The first time into a cgi module (don't include the --with-apache= configure directive). Then compile it as normal the second time to use PHP as an apache module. This will leave the PHP binary in /usr/local/bin (by default).

Running PHP scripts from the command line is the same as writing any other shell script. At the top of the file, add this line:

#!/usr/local/bin/php

Then, chmod the file to make it executable by the user/group your crontab gets run as. Now, you can reference the script just like any other shell script in cron.

jc94062

The file I tested with was CHMODed at 644 and was the following

<?php
//add 1000 to counter
include "../cgi-bin/connect.inc";
$count=mysql_query("SELECT * FROM counter",$db);
while($number=mysql_fetch_array($count)) {
$visit = $number["visitors"];
$visits = ($visit + 1000);
}
$query = "UPDATE counter SET visitors='$visits'";
$result = mysql_query($query);
mysql_close();
?>

I just added 1000 to a counter script. Ran the file manually, worked, ran it via cron, it worked, then redid it to -2000 and then got it working with a db backup to make sure I wasn't going to have conflicts 🙂