206 lines
4.5 KiB
Markdown
206 lines
4.5 KiB
Markdown
<h1><center>shell数组</center></h1>
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------
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## 一:数组
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#### 1.数组介绍
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是若干数据的集合,其中的每一份数据都称为元素
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shell不限制数组的大小,理论上可以存放无限量的数据
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#### 2.数组分类
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普通数组
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只能使用整数作为数组索引/下标(从0开始)
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关联数组
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可以使用字符串作为数组索引/下标
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#### 3.定义数组
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##### 普通数组
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方法一: 一次赋一个值
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```shell
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数组名[索引]=变量值
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[root@xingdiancloud ~]# array1[0]=pear
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[root@xingdiancloud ~]# array1[1]=apple
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[root@xingdiancloud ~]# array1[2]=orange
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[root@xingdiancloud ~]# array1[3]=peach
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```
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方法二: 一次赋多个值
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```shell
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[root@xingdiancloud ~]# array2=(tom jack alice)
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[root@xingdiancloud ~]# array5=(tom jack alice "bash shell")
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[root@xingdiancloud ~]# colors=($red $blue $green $recolor)
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[root@xingdiancloud ~]# array5=(1 2 3 4 5 6 7 "linux shell" [20]=saltstack)
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[root@xingdiancloud ~]# array8=`cat /etc/passwd`
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```
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##### 关联数组
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申明该数组为关联数组
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```shell
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[root@xingdiancloud ~]# declare -A ass_array1
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[root@xingdiancloud ~]# declare -A ass_array2
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```
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方法一: 一次赋一个值
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```shell
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数组名[索引]=变量值
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[root@xingdiancloud ~]# ass_array1[index1]=pear
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[root@xingdiancloud ~]# ass_array1[index2]=apple
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[root@xingdiancloud ~]# ass_array1[index3]=orange
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[root@xingdiancloud ~]# ass_array1[index4]=peach
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```
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方法二: 一次赋多个值
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```shell
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[root@xingdiancloud ~]# ass_array2=([index1]=tom [index2]=jack [index3]=alice [index4]='bash shell')
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```
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一步走
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```shell
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[root@xingdiancloud ~]# declare -A ass_array1='([index4]="peach" [index1]="pear" [index2]="apple" [index3]="orange" )'
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[root@xingdiancloud ~]# declare -A ass_array2='([index4]="bash shell" [index1]="tom" [index2]="jack" [index3]="alice" )'
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```
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#### 4.访问数组元素
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##### 普通数组
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```shell
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[root@xingdiancloud ~]# echo ${array1[0]} 访问数组中的第一个元数
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[root@xingdiancloud ~]# echo ${array1[@]} 访问数组中所有元数 等同于 echo ${array1[*]}
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[root@xingdiancloud ~]# echo ${#array1[@]} 统计数组元数的个数
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[root@xingdiancloud ~]# echo ${!array2[@]} 获取数组元数的索引
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[root@xingdiancloud ~]# echo ${array1[@]:1} 从数组下标1开始
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[root@xingdiancloud ~]# echo ${array1[@]:1:2} 从数组下标1开始,访问两个元素
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```
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##### 关联数组
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```shell
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[root@xingdiancloud ~]# echo ${ass_array2[index2]} 访问数组中的第二个元数
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[root@xingdiancloud ~]# echo ${ass_array2[@]} 访问数组中所有元数 等同于 echo ${array1[*]}
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[root@xingdiancloud ~]# echo ${#ass_array2[@]} 获得数组元数的个数
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[root@xingdiancloud ~]# echo ${!ass_array2[@]} 获得数组元数的索引
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```
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#### 5.数组遍历
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方法一: 通过数组元数的个数进行遍历
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方法二: 通过数组元数的索引进行遍历
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案例一:利用元素进行遍历
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```shell
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#!/bin/bash
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#定义数组
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array=(Mon Tue Wed Thur Fir Sat Sun)
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#数组遍历
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for day in ${array[*]}
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do
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echo $day
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done
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```
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案例二:利用索引进行遍历
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```
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[root@xingdiancloud ~]# cat hello.sh
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#!/bin/bash
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for line in `cat /etc/hosts`
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do
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hosts[++j]=$line
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done
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for i in ${!hosts[@]}
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do
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echo "$i : ${hosts[i]}"
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done
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[root@xingdiancloud ~]# bash hello.sh
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1 : 127.0.0.1
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2 : localhost
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3 : localhost.localdomain
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4 : localhost4
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5 : localhost4.localdomain4
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6 : ::1
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7 : localhost
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8 : localhost.localdomain
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9 : localhost6
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10 : localhost6.localdomain6
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```
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定义换行符
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```shell
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[root@xingdiancloud ~]# cat hello.sh
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#!/bin/bash
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IFS=$'\n'
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for line in `cat /etc/hosts`
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do
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hosts[++j]=$line
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done
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for i in ${!hosts[@]}
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do
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echo "$i : ${hosts[i]}"
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done
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[root@xingdiancloud ~]# bash hello.sh
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1 : 127.0.0.1 localhost localhost.localdomain localhost4 localhost4.localdomain4
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2 : ::1 localhost localhost.localdomain localhost6 localhost6.localdomain6
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```
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#### 6.项目案例
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通过数组统计性别:把要统计的对象作为数组的索引
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```shell
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[root@xingdiancloud ~]# cat sex.txt
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zhangsan f
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lisi m
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[root@xingdiancloud ~]# cat sex.sh
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#!/usr/bin/bash
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declare -A sex
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while read line
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do
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type=`echo $line | awk '{print $2}'`
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let sex[$type]++
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done < sex.txt
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#m作为数组的索引
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for i in ${!sex[@]}
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do
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echo "$i : ${sex[$i]}"
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done
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```
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