shell

#!/bin/bash

#1 输出

function sayHello(){

echo 'hello shell'

}

#sayHello

#2 定义变量

function defVar(){

my_name='neo'

echo ${my_name}

}

#defVar

#3 循环输出

function testFor(){

for script in java php mysql js; do

echo "i am good at ${script}-script"

done

}

#testFor

function testFor02(){

arr=(java php mysql js)

for skill in ${arr[*]}; do

echo "i can use ${skill}-script"

done

}

#testFor02

#4 只读变量

function testReadonly(){

country_name='china'

readonly country_name

country_name='japan'

}

#testReadonly

#5 删除变量

function testDelVar(){

test_del='test del'

unset test_del

echo ${test_del}

}

#testDelVar

#6 单引号

function test01(){

my_name='neo'

echo 'hello, i am ${my_name}'

}

#test01

#7 双引号

function test02(){

my_name='neo'

echo "hello, i am ${my_name}"

}

#test02

#8 拼接字符串 https://blog.csdn.net/lixiaohuiok111/article/details/18313039

function testStrConcat(){

my_name='neo'

hello="hello, i am "${my_name}" !\n"

hello_2="hello, i am ${my_name} !"

echo -e ${hello}${hello_2}

}

#testStrConcat

#9 获取字符串长度

function getStrLen(){

str="abdc"

echo ${#str}

}

#getStrLen

#10 提取子字符串

function subStr(){

str="i am study shell"

substr=${str:5:5} #从第6个字符开始截取5个字符【如果#接到｝后面，变成字符串拼接】

echo ${substr}

}

#subStr

#函数传参

function subStr02(){

str="i am study shell"

substr=${str:${1}:${2}}

echo ${substr}

}

#subStr02 11 5

#11 查找子字符串 https://blog.csdn.net/iamlaosong/article/details/54728393

#【 以下脚本中 "`" 是反引号，而不是单引号 "'"】

function testExpr(){

str="runoob is a great site"

echo `expr index "${str}" is` #查找字符"i或s"的位置

echo $(expr index "${str}" is) #查找字符"i或s"的位置【推荐】

}

#testExpr

#12 Shell数组

function testArr(){

arr=('西游' '水浒' '三国' '红楼梦')

echo ${arr[0]}

echo ${arr[@]} #遍历数组

echo ${arr[*]} #遍历数组

echo ${#arr[@]} #获取数组长度

echo ${#arr[*]} #获取数组长度

echo ${#arr[3]} #获取某个元素的长度

}

#testArr

#13 Shell传递参数 。。。

#14 if判断 注意判断条件[]中的空格

# https://www.jb51.net/article/34332.htm

# https://www.cnblogs.com/avivahe/p/5635911.html

function testIf(){

if [ ${1} -eq 1 ]; then

echo 'num -eq 1'

elif [ ${1} -eq 2 ]; then

echo 'num -eq 2'

else

echo 'num -eq ?'

fi

}

#testIf 2

function testIf02(){

if [ ${1} == 1 ]; then

echo 'num == 1'

elif [ ${1} == 2 ]; then

echo 'num == 2'

else

echo 'num == ?'

fi

}

#testIf02 3

function test04(){

if [ 1 == 1 ]; then

echo  '1 == 1'

else

echo '1 != 1'

fi

if [ 2 -eq 2 ]; then

echo 2 -eq 2

else

echo 2 -ne 2

fi

}

#test04

#15 算数运算符 【2 + 2之间必须有空格】

#``好处是各个版本linux都可用， $()好处是直观

#定义和使用函数 https://blog.csdn.net/zbw18297786698/article/details/77802037

function arithmetic(){

a=${1}

b=${2}

add_val=`expr ${a} + ${b}`

echo "a + b -eq ${add_val}"

sub_val=`expr ${a} - ${b}`

echo "a - b -eq ${sub_val}"

chu_val=`expr ${a} / ${b}`

echo "a / b -eq ${chu_val}"

yu_val=`expr ${a} % ${b}`

echo "a % b -eq ${yu_val}"

a=${b} #变量之间赋值

echo "a -eq ${a}"

}

#arithmetic 20 10

#16 字符串运算符function strExpr(){a=${1}b=${2}if [ ${a} = ${b} ]; thenecho "a 等于 b"elseecho "a 不等于 b"fiif [ ${a} != ${b} ]; thenecho "a 不等于 b"else echo "a 等于 b"fiif [ -z ${a} ]; thenecho "a 长度为 0"elseecho "a长度不为 0"fiif [ ${a} ]; thenecho "a不为空"else echo "a为空"fi}#strExpr "abc" "efg"#17 文件运算符function file(){file=${1}if [ -e ${file} ]; thenecho "文件存在"elseecho "文件不存在"fiif [ -s ${file} ]; thenecho "文件不为空"else echo "文件为空"fiif [ -f ${file} ]; thenecho "普通文件"elseecho "不是普通文件"fiif [[ ! -d ${file} ]]; thenecho "不是文件夹"fiif [ -r ${file} ]; thenecho "可读"elseecho "不可读"fiif [ -w ${file} ]; thenecho "可写"else echo "不可写"fiif [ -x ${file} ]; then echo "可执行"elseecho "不可执行"fi}#touch test.exe#echo "i am a file" > test.exe#chmod +x ./test.exe#file "test.exe"#18 echo命令function readInput(){read nameecho "${name} has been read"}#readInput# 换行输出function output(){echo -e "echo实现换行:\n 加上-e"}#output# 不换行输出function output02(){echo -e "echo实现不换行 \c"echo "test"}#output02# 输出至文件function output03(){echo "give you sth" > myfile}#output03#cat myfile# 显示命令执行结果，使用``[反引号]#echo `date`#echo $(date +%F%n%T)#echo date("Y-m-d H:i:s");#%n: 空格#%F：年月日#%T：时分秒function testPrintf(){printf "%-10s %-8s %-4s\n" 姓名 性别 体重printf "%-10s %-8s %-4.2f\n" 郭靖 男 66.1234printf "%-10s %-8s %-4.2f\n" 杨过 男 48.8803printf "%-10s %-8s %-4.2f\n" 郭芙 女 45.55623}function comment(){%s %c %d %f都是格式替代符%-10s 指一个宽度为10个字符（-表示左对齐，没有则表示右对齐），任何字符都会被显示在10个字符宽的字符内，如果不足则自动以空格填充，超过也会将内容全部显示出来。%-4.2f 指格式化为小数，其中.2指保留2位小数。}#testPrintf#19 流程控制# let命令：http://www.runoob.com/linux/linux-comm-let.html#let 不需要空格隔开表达式的各个字符。#而 expr 后面的字符需要空格隔开各个字符。function testWhile(){i=1while (( ${i} <= 5 )) doecho ${i}let "i++"#i=`expr ${i} + 1`done}#testWhilefunction testWhile02(){echo "按下推出"

echo -n "输入你最喜欢的网站："

while read site

do

echo "${site} is good"

done

}

#testWhile02

function testCase(){

num=${1}

case ${num} in

1) echo '选1'

;;

2) echo '选2'

;;

3) echo '选3'

;;

*) echo '没选'

;;

esac #case反写作为结束

}

#testCase 5

function testBreak(){

num=${1}

while :

do

case ${num} in

1|2|3) echo "您的选择是：${num}"

;;

*) echo "您没有在1-3之间选择，游戏结束"

  break

;;

esac

done

}

#testBreak

#20 函数

function add(){

return $((${1}+${2}))

}

#add 1 2

#echo "1 + 2 = ${?}" #使用${?}获取返回值

function param(){

echo "第一个参数：${1}"

echo "参数总数：${#}"

echo "所有参数：${*}"

}

#param 1 2 3 4 5 6 7 8

#21 输入输出

function testOutput(){

touch users

echo -e "hello file \c" > users

echo "append txt" >> users

cat users

}

#testOutput