Cron is a job scheduling utility present for Linux Users.It runs based on commands specified in a cron tab. With cronjobs, we can determine which task has to run and what time we want the task to execute.
Please refer the below example:
Here I’m trying to execute a pdi job.
1. First I have created a .sh file in which I have saved the PDI( kjb) job details
#!/bin/bash #set -vx export JAVA_HOME=/opt/java/jdk1.8.0_291 JOB="example.kjb"(job name) DIR="/usr/local/scripts/kettle-jobs"(path to job directory) TOOL_BIN_PATH="/usr/local/data-integration/"(tool path used to run job) TOOL="kitchen.sh"(tool used to run job) LOG="/home/gopi/ETLLogs/example.log"(logs) cd ${TOOL_BIN_PATH} ./${TOOL} -file=${DIR}/${JOB} -level=Basic >> ${LOG}
2. Open the crontab using the command below
crontab -e this will open a tab where we save the commands. 10 9 * * 3 /usr/local/scripts/kettle-jobs/example.sh(.sh file path)
Save the above command in crontab and the job will run at scheduled time(in the above example job will run at 9:10 on every Wednesday).
crontab format:
* * * * * file to execute First * is to specify the minutes (0-59) Second * is to specify the hour (0-23) Third * is to specify day of month (1-31) Fourth * is to specify month (1-12) Fifth * is to specify day of week (0-6)
We can also use special symbols like * , – / to specify the multiple values in the field
For example
30 08,09 * 1 * sample.sh : runs every 1st day of month on 8:30 and 9:30
*/30 * * 1 * sample.sh : runs every 30 min on 1st of every month
General Cron Job Syntax:
- crontab -e: to install or update job in crontab
- crontab -l: list crontab entries
- crontab -r: delete our crontab file
- crontab -v: show up the last time we have edited our crontab file
Thank You,
Soni Sammani
Helical IT Solutions
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