functions 函数 #
以update这个脚本为基础编改
作用
- 减少重复代码
#!/bin/bash
release_file=/etc/os-release
logfile=/var/log/updater.log
errorlog=/var/log/updater_errors.log
check_exit_status(){
if [ $? -ne 0 ]
then
echo "An error occured,please check the $errorlog file."
fi
}
if grep -q "Arch" $release_file
then
sudo pacman -Syu 1>>$logfile 2>>$errorlog
check_exit_status
fi
if grep -q "Ubuntu" $release_file || grep -q "Debian" $release_file
then
sudo apt update 1>>$logfile 2>>$errorlog
check_exit_status
#默认yes
sudo apt dist-upgrade -y 1>>$logfile 2>>$errorlog
check_exit_status
fi
CaseStatements #
脚本 #
╭─ ~/shellTest ly@vmmin 22:32:52
╰─❯ cat ./13myscript_cls.sh
#!/bin/bash
finished=0
while [ $finished -ne 1 ]
do
echo "What is your favorite Linux distribution?"
echo "1 - Arch"
echo "2 - CentOS"
echo "3 - Debian"
echo "4 - Mint"
echo "5 - Something else.."
echo "6 - exit"
read distro;
case $distro in
1) echo "Arch is xxx";;
2) echo "CentOS is xbxxx";;
3) echo "Debian is bbbxx";;
4) echo "Mint is xxxxsss";;
5) echo "Something els.xxxxx";;
6) finished=1
echo "now will exit"
;;
*) echo "you didn't enter an xxxx choice."
esac
done
echo "Thanks for using this script."
脚本执行 #
╭─ ~/shellTest ly@vmmin 22:32:11
╰─❯ ./13myscript_cls.sh
What is your favorite Linux distribution?
1 - Arch
2 - CentOS
3 - Debian
4 - Mint
5 - Something else..
6 - exit
3
Debian is bbbxx
What is your favorite Linux distribution?
1 - Arch
2 - CentOS
3 - Debian
4 - Mint
5 - Something else..
6 - exit
u
you didn't enter an xxxx choice.
What is your favorite Linux distribution?
1 - Arch
2 - CentOS
3 - Debian
4 - Mint
5 - Something else..
6 - exit
6
now will exit
Thanks for using this script.
ScheduleJobs #
作用 #
脚本在特定时间运行
安装 #
─ ~/shellTest ly@vmmin 22:37:20
╰─❯ which at
at not found
╭─ ~/shellTest ly@vmmin 22:37:23
╰─❯ sudo apt install at
查看 #
─ ~/shellTest 28s ly@vmmin 22:38:59
╰─❯ which at
/usr/bin/at
示例 #
╰─❯ cat 14myscript_cls.sh
#!/bin/bash
logfile=job_results.log
echo "The script ran at the following time: $(date)" > $logfile
╭─ ~/shellTest ly@vmmin 23:06:05
╰─❯ date
Mon Dec 23 11:06:06 PM CST 2024
╭─ ~/shellTest ly@vmmin 23:06:06
╰─❯ at 23:07 -f /home/ly/shellTest/14myscript_cls.sh
warning: commands will be executed using /bin/sh
job 1 at Mon Dec 23 23:07:00 2024
╭─ ~/shellTest ly@vmmin 23:06:34
╰─❯ cat job_results.log
The script ran at the following time: Mon Dec 23 11:01:23 PM CST 2024
╭─ ~/shellTest ly@vmmin 23:06:46
╰─❯ cat job_results.log
The script ran at the following time: Mon Dec 23 11:07:00 PM CST 2024
╭─ ~/shellTest ly@vmmin 23:07:03
╰─❯ date
Mon Dec 23 11:07:10 PM CST 2024
解释 #
at 23:07 -f /home/ly/shellTest/14myscript_cls.sh
23:07没给日期说明是今天，-f表示运行的是一个文件
查看待运行任务 #
╭─ ~/shellTest ly@vmmin 23:10:53
╰─❯ at 23:12 -f ./14myscript_cls.sh
warning: commands will be executed using /bin/sh
job 2 at Mon Dec 23 23:12:00 2024
╭─ ~/shellTest ly@vmmin 23:11:02
╰─❯ atq
2 Mon Dec 23 23:12:00 2024 a ly
╭─ ~/shellTest ly@vmmin 23:11:04
╰─❯ at 23:13 -f ./14myscript_cls.sh
warning: commands will be executed using /bin/sh
job 3 at Mon Dec 23 23:13:00 2024
╭─ ~/shellTest ly@vmmin 23:11:12
╰─❯ atq
3 Mon Dec 23 23:13:00 2024 a ly
2 Mon Dec 23 23:12:00 2024 a ly
删除作业 #
╭─ ~/shellTest ly@vmmin 23:13:09
╰─❯ at 23:15 -f ./14myscript_cls.sh
warning: commands will be executed using /bin/sh
job 4 at Mon Dec 23 23:15:00 2024
╭─ ~/shellTest ly@vmmin 23:13:14
╰─❯ at 23:16 -f ./14myscript_cls.sh
warning: commands will be executed using /bin/sh
job 5 at Mon Dec 23 23:16:00 2024
╭─ ~/shellTest ly@vmmin 23:13:20
╰─❯ atq
5 Mon Dec 23 23:16:00 2024 a ly
4 Mon Dec 23 23:15:00 2024 a ly
╭─ ~/shellTest ly@vmmin 23:13:24
╰─❯ atrm 4
╭─ ~/shellTest ly@vmmin 23:13:31
╰─❯ atq
5 Mon Dec 23 23:16:00 2024 a ly
日期 #
╭─ ~/shellTest ly@vmmin 23:13:33
╰─❯ atq
5 Mon Dec 23 23:16:00 2024 a ly
╭─ ~/shellTest ly@vmmin 23:14:52
╰─❯ at 23:16 122424 -f ./14myscript_cls.sh
warning: commands will be executed using /bin/sh
job 6 at Tue Dec 24 23:16:00 2024
╭─ ~/shellTest ly@vmmin 23:15:08
╰─❯ atq
5 Mon Dec 23 23:16:00 2024 a ly
6 Tue Dec 24 23:16:00 2024 a ly
CronJobs #
命令的完整路径 #
安排你的bash脚本，在将来的某个时间执行
下面使用完全限定名
╭─ ~/shellTest 19s ly@vmmin 09:08:02
╰─❯ cat 15myscript_cls.sh
#!/bin/bash
logfile=job_results.log
/usr/bin/echo "The script ran at the following time: $(/uar/bin/date)" > $logfile
╭─ ~/shellTest ly@vmmin 09:08:06
╰─❯
which查看命令
ly@vmmin:~/shellTest$ which echo
/usr/bin/echo
ly@vmmin:~/shellTest$ which date
/usr/bin/date
能够保持安全性，还有涉及到路径变量（没法找到，或者找错）
编辑任务 #
╭─ ~/shellTest ly@vmmin 09:17:35
╰─❯ crontab -e
no crontab for ly - using an empty one
Select an editor. To change later, run 'select-editor'.
1. /bin/nano <---- easiest
2. /usr/bin/vim.basic
3. /usr/bin/vim.tiny
Choose 1-3 [1]: 1
#之后会进入nano编辑器并编辑/tmp/crontab.I0AOMk/crontab这个文件（用户自己的，不会干扰其他用户）(crontab.I0AOMk这个文件夹每次都不确定，每次运行crontab -e都是不同文件夹，不过crontab文件内容会跟上次的一样)
编辑内容
# For more information see the manual pages of cro>
#
# m h dom mon dow command
30 1 * * 5 /home/ly/shellTest/15myscript_cls.sh
- 30分钟时执行(每一个小时，即0:30,1:30,2:30），后面两个星号，表示一个月中几号，每年的哪个月，最后这个5表示每星期几（这里是星期五，0跟7都代表星期日）。
- 这个脚本的意思，每周五凌晨1点30分运行
30 1 10 7 4 /home/ly/shellTest/15myscript_cls.sh，如果改成这样，则运行的概率极低。即 每年7月10号且星期四，那天里每一个小时到达30分时执行
#用root用户为某个用户创建任务，不存在则创建新文件并编辑任务，存在则继续编辑之前的任务文件
sudo crontab -u ly -e