Shell functions and arrays

[TOC]

Shell functions and arrays one, Shell function 1.1 function format 1

function name {    commands}

Example 1:

#! /bin/bashfunction inp(){             //定义一个inp的函数echo $1 $2 $3 $0 $#         }inp 1 a 2 b                 //传入参数             //传入参数

Run results

[[email protected] ~]# sh function1.sh1 a 2 function1.sh 4

• [] $: The first parameter is the "2" above
• [] $: The second parameter is the "B" above
• [] $ $: The third parameter is the "3" above
• [] $: The script itself is named "function1.sh" on the
• [] $#: In fact, there are several parameters on this side is "2 B 3 C" that is $# = 4
• [] [email protected]: On behalf of all parameters 2 B 3 C

1.2 Function Format 2

neme() {    commands}

• Example 1

#!/bin/bashsum() {             //定义的函数名为sum    s=$[$1+$2]    echo $s}sum 1 2

Run

[[email protected] ~]# sh function2.sh3

• Example 2

Task: Enter the name of the network card and check the IP address of the network card:

Start with the normal command debug first:

Finally, the valid commands are determined as:

ifconfig |grep -A1 "ens33: " |awk ‘/inet/ {print $2}‘

Function:

#!/bin/baship(){  ifconfig |grep -A1 "$1: " |awk ‘/inet/ {print $2}‘}read -p "please input the eth name: "ethip $eth

Operation Result:

[[email protected] ~]# sh funciton3.shplease input the eth name: eth33192.168.72.130192.168.72.150127.0.0.1192.168.122.1

Modified Complete:

vim funciton3.sh#!/bin/baship(){  ifconfig |grep -A1 "$eth " |awk ‘/inet/ {print $2}‘}read -p "please input the eth name: " ethUseIp=`ip $eth`echo "$eth adress is $UseIp"

Operation Result:

[[email protected] ~]# sh funciton3.shplease input the eth name: ens33: ens33: adress is 192.168.72.130[[email protected] ~]# sh funciton3.shplease input the eth name: ens33:0:ens33:0: adress is 192.168.72.150

Array variables and Functions 2.1 array operation (array note the first is actually a a[0], which is not the same as awk)

[[email protected] ~]# b=(1 2 3 4) //定义一个数组a并赋值 1 2 3[[email protected] ~]# echo ${b[*]} //注意输出a的值的格式1 2 3 4[[email protected] ~]# echo ${b[0]} //注意第一个其实是 b[0]开始1[[email protected] ~]# echo ${b[1]}2[[email protected] ~]# echo ${b[@]}1 2 3 4[[email protected] ~]# echo ${#b[@]} //获取数组的元素个数4[[email protected] ~]# echo ${#b[*]} //获取数组的元素个数4

2.2 Assigning values to arrays, redefining

[[email protected] ~]# b[3]=a[[email protected] ~]# echo ${b[3]}a[[email protected] ~]# echo ${b[*]}1 2 3 a[[email protected] ~]# b[4]=a[[email protected] ~]# echo ${b[*]}1 2 3 a a

2.3 Deletion of array elements

[[email protected] ~]# unset b[2] //删除摸个数组元素[[email protected] ~]# echo ${b[*]}1 2 a a[[email protected] ~]# unset b  //删除整个数组[[email protected] ~]# echo ${b[*]}

2.4 Shards of an array

[[email protected] ~]# a=(`seq 1 10`)[[email protected] ~]# echo ${a[*]}1 2 3 4 5 6 7 8 9 10[[email protected] ~]# echo ${a[@]:3:4} //从第数组a[3]开始，截取4个。4 5 6 7[[email protected] ~]# echo ${a[@]:0-3:2} //从倒数第三个数组开始，截取两个8 9[[email protected] ~]# echo ${a[@]/8/6} //把8换成61 2 3 4 5 6 7 6 9 10  

Shell functions and arrays