Linux 笔记

1.shell 四舍五入

echo 1 |awk 'BEGIN {printf "%.0f\n",((51/10))}

=>5

echo 1 |awk 'BEGIN {printf "%.0f\n",((56/10))}'

=>6

 

2.shell 向上取整

echo 1 |awk '{print int(100/3)==(100/3)?int(100/3):int(100/3)+1}'

 

3.监控命令执行情况

watch -n 1 ls -l

 

4.赋值时，左值包含变量

例如a='11'

b_$a=20会报错

用eval b_$a=20正常

 

5.变量传递

a=10

b=a

echo $b 

=>a

echo ${!b}

=>10

 

来源：https://www.cnblogs.com/xia-dong/p/11803617.html