I have a lot of php-scripts which I would like to execute as cronjob. It´s important that those scripts are executed in the right order and are not running at the same time. How can I set up cronjobs which run after each other?
Each cron job runs when it's scheduled to run, regardless of whether any other cron jobs happen to be running.
Just make a cron job that executes several commands sequentially:
* * * * * command1; command2; command3
The command (in this case command1; command2; command3) is executed by /bin/sh (or by a shell you can specify by setting SHELL in your crontab). /bin/sh, or any shell worthy of the name, knows how to execute commands sequentially.
If there are a lot of commands you can put them into a shell script and execute that from cron.
Related
I can't wrap my head around this concept
If a cron job is set to execute a particular script every 5 minutes and the task the script is performing happens to be very long
What will happen if cron job re execute the script after 5 minutes and the script is not done executing the prior task will this cause the prior task to abort and restart again
Or will the server know its suppose to queue it and wait for the prior task before re executing the script
It is neither. The two tasks overlap, and run at the same time.
Cron jobs don't cancel each other unless they try to lock and access the same files, or the scripts have some other conflicts. You can of course make them cancel each other if you want, though.
The server is none the wiser, and the tasks don't wait for previous executions unless you explicitly add such details, for example, by using flock or pgrep to check for previous executions still running.
The following example entry in cron tab checks if the script is already running, and only runs if the script (cron.sh) is not already running.
* * * * * /usr/bin/pgrep -f /path/to/cron.sh > /dev/null 2> /dev/null || /path/to/cron.sh
There are 2 shell scripts, test.sh & execute.sh, I need to run both the shell scripts using single cron job. Once the test.sh has completed execution then I need to run execute.sh sequentially. execute.sh must not be triggered until test.sh has executed successfully. execute.sh takes one parameter i.e properties file /user/abc/config.properties. I need to run this every one hour recursively. How to do it?
If I understood you correctly, a cron job like this would do:
0 * * * * /path/to/test.sh && /path/to/execute.sh /user/abc/config.properties
I am using Linux Centos to schedule a job.
I have created a shell script file called Im_daily_loads.sh to run the job at 12:42PM everyday.
with the following comands:
#!/bin/sh
42 12 * * * cd $pdi; ./kitchen.sh -file="/opt/kff/software/pdi/5.0.1.A/data- integration/projects/IML/code/stg/IML_Load_Frm_SRC_To_PSA.kjb" -level=Basic > -logfile="/opt/kff/software/pdi/5.0.1.A/data-integration/projects/IML/log/iml_daily_loads.err.log"
Then loaded the file into crontab by using the issuing the following command crontab Im_daily_loads.sh, but my job is not running.
What would be the problem?
Why not just use
crontab -e
as the user you plan to execute the job as, enter the job, save and exit the editor?
Also, it looks like you need to define $pdi in your script. How is crontab supposed to know where your script is located?
first , run a very simple job to be shure crontab works at all.
for example
set > /tmp/crontab_works.log 2>&1
it will write down all variables. so you will see not all variables available in crontab
I have a shell script that I have scheduled using cron using a command:
0 10 * * * /directory/Script.sh > /directory/log/output.log
The script is scheduled to run at 10 AM everyday. The script executes but produces output files only with headers, no content is there.
The script produces two output files. When I run the script manually it works fine. But when scheduled it is not producing the correct output.
Help me out.
Thanks
Multiple reasons
1> Check full path of all executable in the script.
2> Ensure all environment variables are set accordingly
3> Check the script when run from the same user as the cron is executing.
Technically there is no difference between manually running a script and scheduling from cron
I made a shell script and registered to execute every 20 minutes.
Here is my crontab code.
*/20 * * * * sh /mypath/run_myprocess.sh &> /dev/pts/34
I editted code like this in order to see whether my process run correctly.
I get the result '/dev/pts/34' from tty command in terminal.
However, does anyone know how to use linux command results(in this case: /dev/pts/34)
in crontab? This is because I will use several terminal to run my tasks.
For example, in shell script, I can use linux command result in the form of $(command) such as
echo "$(date)"
directly.
Plus, if I type something on the terminal during process running with crontab, it actually gives result. For example,
Process is running........
ls
backup backup.sh Desktop Task_Folder shared_folder
[UserID] ~ #
So I guess cron jobs run correctly but in background.
Please help me to find out how can I bring cron jobs in foreground.
If you start a job on your console and background it you can then bring it to foreground. If the task is not yours or not started on your terminal then you can not.