Linux Learning 134 Unit 3

Unit three of the second book

1. System Delay Task Initiation command

[[email protected] mnt]# at 11:03

at> touch/mnt/file{1..10} # #要执行的命令

at> <EOT>< Press ctrl+d> # #任务发起

Job 2 at Sat Nov 7 11:03:00 2015

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[email protected] mnt]# at-l # #查看任务列表

2 Sat Nov 7 11:03:00 a root

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[email protected] mnt]# ATRM 2 # #删除编号为2的人物

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[email protected] mnt]# at Now+1min # #任务延迟一分钟执行

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Use Control for 3.at commands

/etc/at.deny # #默认存在系统中, users who appear in this list are forbidden

Test # #禁止test执行at

/etc/at.allow # #默认在系统中不存在,

# #但是当此文件存在时,

# # #deny文件失效,

#并且所有普通用户能执行at的权力被禁止, only users in this file can perform an at

Student # #系统中的普通用户只有student可以使用at

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4. Schedule recurring Tasks

Initiation Mode 1

Crontab

- e # #编辑定期任务

- L # #显示定期任务

- R # #删除定期任务

crontab format

minutes hours Day month week

minutes /numbers # #每隔几分钟, etc., hours, days, months, weeks apply

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Initiation Mode 2

Vim/etc/cron.d/ps # #ps文件名称任意

minutes hours Day month week user commands

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4.crontab Usage Limits

/etc/cron.deny # #默认存在系统中, users who appear in this list are forbidden

Test # #禁止test执行crontab

/etc/cron.allow # #默认在系统中不存在,

# #但是当此文件存在时,

# # #deny文件失效,

#并且所有普通用户能执行crontab的权力被禁止, only users in this file can perform crontab

Student # #系统中的普通用户只有student可以使用crontab

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5. System Temp File

Vim/usr/lib/tmpfiles.d/xxx.conf

type name Permissions All All Groups time of existence (S M d)

Systemd-tmpfiles --create/usr/lib/tmpfiles.d/xxx.conf # #创建

Systemd-tmpfiles --clean /usr/lib/tmpfiles.d/xxx.conf # #清理

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Linux Learning 134 Unit 3