本文将指导您安排计划在一天中的特定时间执行的cron作业。
MIN HOUR Day of month Month Day of Week Command 0-59 0-23 1-31 1-12 0-6 linux command or script
要查看机器上存在的cron作业列表，请运行以下命令
# crontab -u test1 -l no crontab for test1
#crontab -u test1 -e no crontab for test1 - using an empty one Select an editor. To change later, run 'select-editor'. /bin/ed /bin/nano <---- easiest /usr/bin/vim.basic /usr/bin/vim.tiny Choose 1-4 [2]:2 # Edit this file to introduce tasks to be run by cron. # # Each task to run has to be defined through a single line # indicating with different fields when the task will be run # and what command to run for the task # # To define the time you can provide concrete values for # minute (m), hour (h), day of month (dom), month (mon), # and day of week (dow) or use '*' in these fields (for 'any').# # Notice that tasks will be started based on the cron's system # daemon's notion of time and timezones. # # Output of the crontab jobs (including errors) is sent through # email to the user the crontab file belongs to (unless redirected). # # For example, you can run a backup of all your user accounts # at 5 a.m every week with: # 0 5 * * 1 tar -zcf /var/backups/home.tgz /home/ # # For more information see the manual pages of crontab(5) and cron(8) # # m h dom mon dow command
cron的基本用法是在特定时间执行作业，如下所示。这将在每天的9 AM和6 PM执行完整备份Shell脚本(backup_files.sh)。
00 09-18 * * * /home/test1/backup_files.sh
00 – 00th Minute 09-18 – 09 AM & 06:00PM * --Every day of the Month * -- Every Month. * --Every day of the week
在配置结束时，您应该能够每天在特定时间从特定用户运行脚本或命令。这样，我们可以为任何用户指定Cron作业。这些Cron类型通常用于备份用户数据，例如桌面，下载等。