cron syntax code example
Example 1: cron example
crontab -e # to edit
10 * * * * /bin/sh backup.sh # every hour at 10"
0 */4 * * * /bin/sh backup.sh # every 4 hours at 0"
0 9-17 * * * /bin/sh backup.sh # every hour at 0" between 9 and 17
0 2 * * * /bin/sh backup.sh # daily at 2am
0 0 * * MON /bin/sh backup.sh # every Monday at 0am
0 0 * * 1-5 /bin/sh backup.sh # daily from Monday to Friday at 0am
0 0 * * 0 /bin/sh backup.sh # weekly on Sunday
0 0 1 * * /bin/sh backup.sh # monthly (1rst day at 0am)
0 0 1 */3 * /bin/sh backup.sh # every quarter (1rst day at 0am)
0 0 1 1 * /bin/sh backup.sh # yearly (01/01)
Example 2: cronjob set time
Min
Hour
Day of Month
Month
Day of Week
Example 3: cron
# 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
# Set the hardware clock to keep it in sync with the more accurate system clock
03 05 * * * /sbin/hwclock --systohc
# Perform monthly updates on the first of the month
# 25 04 1 * * /usr/bin/dnf -y update