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Cron job on Ubuntu for php
I am running and ubuntu server and wanted to run a php script every day. I have done some research and found that cron is the best way of doing this however, this is where i got stuck, a lot of the information on the internet about cron is very hard to follow and understand.
So i wanted to execute a simple php script once a day, the script i made for testing simply just deletes a record from a database, but the real script will do a lot more.
I tried setting up a task through plesk which is provided through my web host service but it didn't seem to execute when i wanted it to, i used 1 for minutes, 22 for hours, * for day, * for week and * for month and thought this would execute every day at 22:01.
I have the directories on my server:
cron.hourly
cron.daily
cron.weekly
cron.monthly
I thought i could dump i file in there and it would execute for example every day, but i'm guessing i need to make a cron script to call a php script right?
If i were to go the way of putting a file in the cron.daily folder how would i go about it?
Also if there are any steps i need to take on the php side please let me know?
Thanks a lot for your time.
There's couple of ways to setup cron job. Assuming you got shell access you could do crontab -e from console and define job there, i.e. like this:
1 22 * * * command
which would trigger command (whatever it is) at 22:01 each day (not sure why you set minutes to 1 instead of 0 though). To launch PHP script from there you would either have to install php-cli, and then invoke it that way:
1 22 * * * <path>/php -q script.php
You can also call bash script here, to setup all the stuff like paths etc and then call your php script form bash - sometimes it is simpler to do that way instead of crafting way too long command line for cron. And it's simpler to update it later. also, you could turn your php script into bash-runnable script by setting it execution bit (chmod a+x script.php) and adding shell's shebang:
#!/usr/bin/php -q
<?php
...
If your script got too many dependencies and you'd prefer to call it via web, you could use wget to mimic a browser. so your command would be:
/usr/bin/wget --delete-after --quiet --spider <URL-TO-YOUR-SCRIPT>
wget manual can be accessed by man wget or wget -h, or is on this website. Aternatively you may use HEAD tool from perl-www package - but it requires perl while wget is a standalone tool. If you use HTTPS with self signed certs, add --no-check-certificate to your invocation arguments. And you may also want to setup .htaccess and limit web access to your cron script to localhost/127.0.0.1
every minute:
* * * * * /path/script.php
every 24hours (every midnight):
0 0 * * * /path/script.php
Se this reference for how crontab works: http://adminschoice.com/crontab-quick-reference, and this handy tool to build cron jobx: http://www.htmlbasix.com/crontab.shtml
Related
I have installed this extension to assist me in my cron jobs omnilight/yii2-scheduling. The extension has good documentation that is why I settled on it amidst all the other cron-jobs extensions available for yii2. However, I am stack at some place that I need assistance. There is a place where I am asked to put a single line of code on the crontab:
* * * * * php /path/to/yii yii schedule/run --scheduleFile=#console/config/schedule.php 1>> /dev/null 2>&1
However, I am not sure where to place it, i.e. where is the crontab in yii2? anyone who has used this extension and is able to get it running to assist me here.
Maybe a little later but you must put that in the crontab, a cron is :
cron is a Unix, solaris, Linux utility that allows tasks to be automatically run in the background at regular intervals by the cron daemon
and the crontab is where are stored all this crons. To edit this file you must use in terminal:
crontab -e
Put that line here. Save and you are ready to go.
I am using a plugin in moodle that requires running cron. I manually run localhost/moodle/admin/cron.php and it worked. So my question is how can I run this script all the time and not manually. I read about C panel but I'm not sure how to use it.
Any advise is appreciated. Thanks in advance.
If you go to your cpanel on your host, then go to the cron options. It should also you how often you want the cron to run and a script to run.
The script is
usr/bin/php /path/to/moodle/admin/cli/cron.php >/dev/null
If you choose to run every 15 minutes then you should see something like this after setting up cron.
*/15 * * * * /usr/bin/php /path/to/moodle/admin/cli/cron.php >/dev/null
http://docs.moodle.org/25/en/Cron
Hi I'm a first year game programing student learning Unix Bash, I have run into a problem trying to understand crontab. I'm trying to do some rather simple things, checking to see if I am online, getting information about a given website, and ping another website to verify it is online. My script file does all of this without fail, however when I try to perform these tasks through crontab I get emails telling me absolutely nothing but jibberish. The output basically just tells me that I am trying to do all these things, but it doesn't output the results. I'm not sure where I am going wrong.
Just to verify I do have permission on the system to use crontab, and I have the script running every minute while I am trying to get it working. I'm hoping someone can point me in the right direction, all of my research online has really just led me astray.
This is my crontab
SHELL=/bin/bash
PATH=/sbin:/bin:/usr/sbin:/usr/bin
HOME=/
LOGNAME=username
* * * * * /bin/bash /home/students/~/online.sh
30 23 1 * * rm online.log
this is my script
touch online.log
who | grep username >> online.log ; whois yahoo.ca >> online.log ; ping -c 1 www.google.com >> online.log
You need to use absolute paths in your scripts if you want to execute those using cron.
Note that cron executes in a different environment from what you get while executing a script on the command line. For example, changes lines like
touch online.log
to include the absolute path to online.log.
The output is being redirected into online.log, so you need to look there, not in your emails. If you want the output to be in the emails as well, you should look into using tee instead of a redirection.
I've recently started a simple project, just to help me learn the BASH scripting language a little better. Anyway, this script is set to alternate/rotate the user's desktop background/wallpaper at a given interval.
Given that this task would most likely be done every 30 minutes to 1 hour, how should I go about doing this. Would 30 minute/1 hour timers be very inefficient? Or, could cronjobs do a better job for me?
Also, how could I get this script to run in the background, so that a terminal window is not always required to be open?
Could you provide some sort of an idea into the syntax, if you can, as well.
This would be a suitable job for cron. cron would take care of invoking the script at regular intervals. You would not then have to be concerned in your script when the script should run and managing a script running in the background.
Running in the background would be extravagent as the script does not need to do much - not much more than change the current desktop setting. Typically the script would only take a small fraction of a second to complete the task.
cron entries have six fields-:
mins hours day month day-of-week path_to_command
0-59 0-23 1-31 1-12 0-6 command
days of the week start on Sunday. 0=Sunday, 1=Monday etc.
cron entry to run the script every hour for all days and months-:
0 * * * * /path/change_wallpaper.sh
to list your current cron jobs, type
crontab -l
Edit your cron jobs and add the new cron entry-:
crontab -e
Check the new setting is in place -:
crontab -l
I would personally run the script using following crontab:
0 * * * * $HOME/changewallpaper.sh
which you can install as a user with this command
crontab -e
Other solutions include running daemon script from file ~/.xprofile
For more information please refer to
man crontab
man 5 crontab
Also check out this project Variety.
Also, how could I get this script to run in the background, so that a terminal window is not always required to be open?
That would be a daemon. And there's no need to write your own. It's a bit tedious in bash if you want pidfile, start|stop|restart etc. Just add a new cronjob which'll execute your script every n minute or something.
Edit your cronjobs
crontab -e
Execute script every 30 min: (not the same as 30, which would do it every hh:30!)
*/30 * * * * /path/to/your/script
Restart cron. How depends on distro, here's Ubuntu:
service cron restart
List cronjobs:
crontab -l
I am really new to Linux and I apologize if this is rudimentary, but I have Google'd to find examples with no clarity and I am confused. (the question relates to a server running CentOs 6)
My questions are:
I am not sure what is the default directory that I should store a .sh file in so that a cron job can run it.
Is the syntax and sequence of my code in .sh file below correct?.
I have tested the TSQL and its fine.
#! SQL="DELETE FROM messages WHERE date < DATE_SUB(CURDATE(), INTERVAL 7 DAY)"
MYSQL_USER="root"
MYSQL_PASS="xxxxxx"
MYSQL_DB="mydb"
I understand that the cron should contain this to do it on a daily basis:
0 0 * * *
But I am just having some apprehension of how to put it all together so I don't screw things up. A full example or explanation or a reference link would be greatly appreciated.
I believe that cron will execute the script from whichever directory it is in, given that:
the file has execution permission for the user that cron runs as (usually root if job is configured in the system-wide crontab)
the cron line specifies the full path to the script
So, if your script is /opt/script.sh, specifying this in cron:
0 0 * * * /opt/script.sh
will execute script.sh each day in 12:00am.
Please note that if this is the system-wide crontab (/etc/crontab) it should also include a username as which to execute the command:
0 0 * * * username /opt/script.sh
Also, something to make sure when working with cron is to either use full paths when calling external commands from the script or to set up the PATH variable (either in the script itself or on the crontab file). This is needed because usually the environment in which cron jobs are run is pretty restricted.
Another thing to have in mind is that if any output is generated by a cron job this output is sent via mail to the user executing the cron. So to have some feedback from the script you have to either set up the system so that the mail message ends up in a mailbox which is read by a human being or the script sends all of it's output to a log file or syslog.