Answer Posted / subbareddy kake

at:If you want postpone the excution of process we can use
at command.but you should specify time for running process.

batch:This command also works like at but here no need
specify the time.Unis OS itself decide the time for
processing the job.

crontab:If you want run some jobs at daily or some times u
can keep those jobs in crontab file.those are cronjobs.

crontab -l:To open crontab file
crontab -e:To edit the crontab file
crontab -r:To remove the crontab file

* * * * * job name

star1:min(1 to 59)
star2:hour(0 to 23)
star3:day of the month(1 to 31)
star4:month(1 to 12)
star5:day of the week(0 to 6)

here zero indicates sunday

15 05 * * 1-5 job schedule----->This job will run everday
at 5:15am except sunday.


Like this so many jobs we can keep in one crontab file.

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