shell常用脚本
计算程序运行时间
按秒计算
#!/bin/bash
start=$(date +%s)
#你要执行的操作
end=$(date +%s)
take=$(( end - start ))
echo Time taken to execute commands is ${take} seconds.
按毫秒计算
#!/bin/bash
start=$(date +%s%3N)
# 你要执行的操作
end=$(date +%s%3N)
take=`expr ${end} - ${start}`
echo Time taken to execute commands is ${take} ms.
循环执行
#!/bin/bash
#一般先声明数组,在里面填循环的东西
ips=(192.168.1.1 192.168.1.2)
for ip in ${ips[@]}
do
echo "${ip}"
done
# 从第二个元素开始
for ip in ${ips[@]:1}
do
echo "${ip}"
done
while true:
do
echo "loop"
done
n=0
while [ $n -le 100 ]
do
echo "loop"
let n++
done
条件判断
字符串判断
#!/bin/bash
ip="192.168.1.1"
if [ "${ip}"x == ""x ];
then
echo "eqal"
fi
数字判断
#!/bin/bash
ip=192
if [ ${ip} -eq 192 ];
then
echo "equal"
fi
文件判断
#!/bin/bash
ip="192"
if [ -d ${ip} ];
then
echo "exist"
fi