如何在 Linux 系統中為特定使用者新增計劃任務
在本文中,我們將教會你如何安排計劃任務在一天中的特定時間執行。
計劃任務的一般語法
MIN HOUR Day of month Month Day of Week Command 0-59 0-23 1-31 1-12 0-6 linux command or script
要檢視機器上存在的計劃任務列表,請執行以下命令
# crontab -u test1 -l no crontab for test1
要將新的計劃任務新增到 Test1 使用者,請執行以下命令
#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
為不同使用者安排任務
cron 的基本用法是在特定時間執行任務,如下所示。這將在每天上午 9 點和下午 6 點執行完全備份 shell 指令碼 (backup_files.sh)
00 09-18 * * * /home/test1/backup_files.sh
說明
00 – 00th Minute 09-18 – 09 AM & 06:00PM * --Every day of the Month * -- Every Month. * --Every day of the week
結束語
在配置結束時,你應該能夠在每天的特定時間從特定使用者處執行指令碼或命令。這樣,我們可以為任何使用者指定計劃任務。此類計劃任務通常用於備份使用者資料,例如桌面、下載等。
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