Recently in a community with PHP, writing to calculate the highest number of people, successfully debug the PHP as a shell script directly on the server run.
When making a community, it is often necessary to count data such as the number of people on the line. It is a common practice to put this code on a user login or a page to trigger the code to run when the user logs on or accesses it. This can cause a problem if the code teaches complexity and significantly slows down the normal invocation speed of the page.
With this feature of PHP, plus the Linux crontab instructions, you can automatically schedule a php file (counting online numbers, etc.).
Specific methods:
When you install PHP, an executable file is generated with the file name PHP. copy it to/usr/local/bin.
Execute PHP Program in terminal mode: Php-q onlinnum.php
Notice that PHP was originally applied to the Web application, so it will send out the HTML header, but here we are to use PHP as the Shell script, "-Q" means not to send out the HEADER. You can try not to add the "-Q" Display results.
At this point you can already execute the PHP code in the terminal mode. Oh, you can try to execute the code you wrote before.
Linux command: Cron daemon
This is a resident service in a system that performs routine work, such as checking disks once a day or once a month. Cron Daemon checks the scheduled worksheet (crontab) every minute to see if there are instructions to execute, and all the output is sent to the user in mail.
Set crontab
Command: CRONTAB-E
This command calls the VI Editor to edit the list of executions. For example
&nbs p; 0 0 1,15 * * fsck/home
&nbs p; 1 * * * */home/gull/onlinnumber
Each row represents a scheduled work, with a total of 5 fields at the scheduled time before the instruction, with a space interval, from left to right, as follows:
Field &nbs p; Description
---------------------- ----
Minutes from 00 to 99
o ' clock from 0 to 24
Day &nbs p; from 01 to 31
Month &nbs p; from 01 to 12
Week from 01 to 07, representing Monday to Sunday
* Number means "every", such as daily execution, in the third column fill in the * number
So the two tasks in the example above are:
Check/home disk 1th and 15th per month
The first minute of every hour executes/home/gull/onlinnumber this file
View Crontab:crontab-l
Delete Crontab:crontab-r
Oh, here, you should know how to use PHP and crontab command to count the number of people online?
Need to note:
If you have a database in PHP, such as Oracle, you also need to export Oracle's environment settings in the script execution. Because the script executed under Cron is executed without logging in, there are fewer environment variables set in the system, and there are problems when connecting to the database.
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