Linux Task Scheduler

Task Scheduler: Backup data at specific times, restart services, shell scripts, individual commands, and more.

Task Scheduler Profile: Cat/etc/crontab

[Email protected] ~]# Cat/etc/crontab

Shell=/bin/bash

Path=/sbin:/bin:/usr/sbin:/usr/bin

Mailto=root

# for details see Mans 4 Crontabs

# Example of Job definition:

#.----------------Minute (0-59)

# | .-------------Hour (0-23)

# |  | .----------Day of Month (1-31)

# |  |  | .-------month (1-12) OR jan,feb,mar,apr ...

# |  |  |  | .----Day of Week (0-6) (sunday=0 or 7) or Sun,mon,tue,wed,thu,fri,sat

# |  |  |  | |

# * * * * * * user-name command to be executed

Shell script, PATH environment variable, mailto send mail to WHO

Time:

Minutes, hours, days of the month, month, week, and finally, commands that need to be executed.

CRONTAB-E the task plan that needs to be performed.

Scripts executed 3 o'clock in the morning per day

0 3 * * */bin/bash/usr/local/sbin/123.sh >>/tmp/123.log 2>>/tmp/123.log

1 to 10th of the 3 points of the month can be divisible by 2, Week 2 and Week 5,

0 3 1-10 */2 2,5/bin/bash/usr/local/sbin/123.sh>>/tmp/123.log 2>>/tmp/123.log

To use an absolute path, for example iptables can be written as an absolute path or added to path

/usr/sbin/iptables

Start the service:

Systemctl Start Crond.service

To see if it starts:

PS aux |grep

Or:

Systemctl Status Crond

Crontab-u,-E,-L,-R

Format: Time-sharing Week user command

File/var/spool/cron/username

Sub-range 0-59, time range 0-23, day range 0-31, month range 0-12, week 1-6

Available formats 1-5 indicates a range of 1 to 5

Available formats 1 or 2 or 3

Available formats */2 represent numbers that are divisible by 2, such as hours, that is, every 2 hours to ensure that the service is in the boot state

Linux Task Scheduler