标签：one 任务 The 变化 sum 猜数字 func 系统负载 user
1，每隔3秒，打印一次系统负载
#!/bin/bash while true do uptime sleep 3 done
2，把监控结果保存到文件，在后台执行，然后用tail -f监控文件变化
ghostwu@dev:~/linux/shell/flow_control$ sh while.sh & [1] 12867
#!/bin/bash while true do uptime >> log.txt sleep 3 done
ghostwu@dev:~/linux/shell/flow_control$ tail -f log.txt 06:14:32 up 33 min, 1 user, load average: 0.33, 0.35, 0.32 06:14:35 up 33 min, 1 user, load average: 0.33, 0.35, 0.32 06:14:38 up 33 min, 1 user, load average: 0.31, 0.34, 0 ...
3，进程调度相关命令
fg: 把当前脚本或者任务放到前台执行。如果指定某个任务：fg 任务编号。 任务编号通过jobs查询
bg: 把任务放到后台执行
jobs:查看当前执行的脚本或者任务
ctrl+z:暂停执行当前的脚本
sh while1.sh & : 加上&，表示后台执行脚本
ghostwu@dev:~/linux/shell/flow_control$ fg sh while.sh ^Z [1]+ Stopped sh while.sh ghostwu@dev:~/linux/shell/flow_control$ jobs [1]+ Stopped sh while.sh ghostwu@dev:~/linux/shell/flow_control$ bg [1]+ sh while.sh & ghostwu@dev:~/linux/shell/flow_control$ jobs [1]+ Running sh while.sh & ghostwu@dev:~/linux/shell/flow_control$ sh while.sh & [2] 13411 ghostwu@dev:~/linux/shell/flow_control$ jobs [1]- Running sh while.sh & [2]+ Running sh while.sh & ghostwu@dev:~/linux/shell/flow_control$ fg sh while.sh ^Z [2]+ Stopped sh while.sh ghostwu@dev:~/linux/shell/flow_control$ bg [2]+ sh while.sh & ghostwu@dev:~/linux/shell/flow_control$ jobs [1]- Running sh while.sh & [2]+ Running sh while.sh &
4，用while循环打印0, 1, 2, 3, 4
#!/bin/bash i=0 while [ $i -lt 5 ] do echo $i (( i++ )) done
两个中括号也可以
#!/bin/bash i=0 while [[ $i -lt 5 ]] do echo $i (( i++ )) done
还可以用计算表达式
#!/bin/bash i=0 while (( i < 5 )) do echo $i (( i++ )) done
5，计算1....100的和
ghostwu@dev:~/linux/shell/flow_control$ sh sum.sh 1+2+3..+100=5050 ghostwu@dev:~/linux/shell/flow_control$ cat sum.sh #!/bin/bash i=1 sum=0 while (( i <= 100 )) do (( sum = sum + i )) (( i++ )) done echo "1+2+3..+100="${sum}
6，猜数字
#!/usr/bin/bash sum=$((RANDOM%51)) echo "需要你猜的数是:"$sum sleep 1 echo "请输入1-50之间的数,开始猜吧!" count=0 function type_num(){ read -p "请输入一个数吧:" n expr $n + 1 &>/dev/null if [ $? -ne 0 ]; then echo "请输入一个数字" type_num fi } function guess(){ (( count++ )) if [ $n -eq $sum ]; then echo "你猜中了,你的次数是:"${count} if [ $count -lt 3 ]; then echo "你太厉害了" elif [ $count -ge 3 -a $count -lt 6 ]; then echo "还是不错的,加油" else echo "你有点水啊" fi exit 0 elif [ $n -gt $sum ]; then echo "猜大了" type_num else echo "猜小了" type_num fi } function main(){ type_num while true do guess done } main
标签：one 任务 The 变化 sum 猜数字 func 系统负载 user
原文地址：https://www.cnblogs.com/ghostwu/p/9114660.html
