How can I write a Crontab that will run my /home/username/test.sh script every 2 hours?
7 Answers
Just do:
0 */2 * * * /home/username/test.sh The 0 at the beginning means to run at the 0th minute. (If it were an *, the script would run every minute during every second hour.)
Don't forget, you can check syslog to see if it ever actually ran!
1The line should read either:
0 0-23/2 * * * /home/username/test.sh or
0 0,2,4,6,8,10,12,14,16,18,20,22 * * * /home/username/test.sh 0 */2 * * * The answer is from . It is interesting.
0 */1 * * * “At minute 0 past every hour.”
0 */2 * * * “At minute 0 past every 2nd hour.”
This is the proper way to set cronjobs for every hr.
To Enter into crontab :
crontab -e write this into the file:
0 */2 * * * python/php/java yourfilepath Example :0 */2 * * * python ec2-user/home/demo.py
and make sure you have keep one blank line after the last cron job in your crontab file
first do crontab -l to see your existing crontab and jobs if you don't anything then do crontab -e
check you editor maybe VI or nano or anything like that.. go to insert mode by 'i', command should be like (cron expression)[space](program execution address from home)[space](your script address from home)
example (0 /2 * * * /conda///bin/python3 ///USERNAME/TEST_PYTHON_SCRIPT.py >> execution_log.txt)
execution_log.txt will have the execution log of your script.
once you have your command correctly placed exit the editor by saving the file for nano -> ctrl + x for vi -> :wq!
check your scripts with some email/print statement.
If one needs a simple cron schedule generator, this one can do that well: _/2___*
* */2 * * * 
