shell脚本-02

小鱼儿 2022-05-24 11:24 114阅读 0赞

**shell字符串:**

str="sasa"
    echo "hello,i am \"${str}\""

country="china"
    city="qingdao"
    
    echo "${city},${country}"
    
    echo "获取字符串长度"
    echo "${#country}"
    
    echo "截取字符串，从0开始"
    echo "${country:1:3}"
    
    echo "查找子字符串"
    greet="hello heihei haha"
    echo `expr index "${greet}" he`

root@VM-0-17-ubuntu:/home/bash# ./bash13.sh
    hello,i am "sasa"
    qingdao,china
    获取字符串长度
    5
    截取字符串，从0开始
    hin
    查找子字符串
    1

**数组：**

#数组的定义
    echo "数组的定义"
    arr=(zhangsan lisi wangwu)
    echo ${arr[*]}
    
    arr=(
    zhangsan
    lisi
    wangwu
    zhaoliu
    )
    echo ${arr[*]}
    
    arr[0]=zhangsan
    arr[1]=sasa
    arr[2]=lisi
    echo ${arr[@]}
    
    #获取数组长度
    
    echo "获取数组长度"
    echo ${#arr[*]}

root@VM-0-17-ubuntu:/home/bash# ./bash14.sh
    数组的定义
    zhangsan lisi wangwu
    zhangsan lisi wangwu zhaoliu
    zhangsan sasa lisi zhaoliu
    获取数组长度
    4

**echo命令：**

str=qqq
    echo 输出时双引号可以忽略
    echo ${str}
    echo "${str}"
    
    echo 显示转义字符
    echo \"${str}\"
    
    echo 显示换行
    echo -e "hello \n sasa"
    echo "zhangsan"
    
    echo 显示结果重定向到文件,此时file2文件中该字符串
    echo "line one" >file2.txt
    
    echo 显示命令执行结果
    echo `date`

root@VM-0-17-ubuntu:/home/bash# ./bash15.sh
    输出时双引号可以忽略
    qqq
    qqq
    显示转义字符
    "qqq"
    显示换行
    hello
     sasa
    zhangsan
    显示结果重定向到文件,此时file2文件中该字符串
    显示命令执行结果
    Sat May 26 11:52:40 CST 2018

**if else 语句**

cho if [] then ... fi
    echo if [] then ... else ... fi
    echo if [] then ... elif []  then ... elif [] then ... else ... fi
    
    echo [] 条件判断
    
    a=10
    b=20
    
    if [ ${a} == ${b} ]
    then
            echo ==
    else
            echo !=
    fi
    
    echo test 条件判断
    
    if test ${a} == ${b}
    then
            echo ==
    else
            echo !=
    fi
    
    if [ ${a} == ${b} ]
    then
            echo ==
    elif [ ${a} -gt ${b} ]
    then
            echo "a>b"
    else
            echo "a<b"
    fi

root@VM-0-17-ubuntu:/home/bash# ./bash16.sh
    if [] then ... fi
    if [] then ... else ... fi
    if [] then ... elif [] then ... elif [] then ... else ... fi
    [] 条件判断
    !=
    test 条件判断
    !=
    a<b

**case in语句**

echo please enter a num between 1 and 4
    read num
    case ${num} in
            1)echo 1111111
            ;;
            2)echo 222222
            ;;
            3)echo 33333
            ;;
            4)echo 4444444
            ;;
            *)echo "not in 1-4,is ${num}"
            ;;
    esac

root@VM-0-17-ubuntu:/home/bash# ./bash17.sh
    please enter a num between 1 and 4
    7
    not in 1-4,is 7
    root@VM-0-17-ubuntu:/home/bash# ./bash17.sh
    please enter a num between 1 and 4
    3

argu1=${1}
    case ${argu1} in
            [a-z]|[A-Z])
                    echo "a-Z"
            ;;
            [0-9])
                    echo "0-9"
            ;;
            *)
                    echo "what?"
            ;;
    esac

root@VM-0-17-ubuntu:/home/bash# ./bash18.sh  1
    0-9
    root@VM-0-17-ubuntu:/home/bash# ./bash18.sh  y
    a-Z
    root@VM-0-17-ubuntu:/home/bash# ./bash18.sh  *
    what?

**for循环**

echo 每次输出的内容根据空格作为分割
    for loop in 1 2 3 4 5
    do echo "this is ${loop}"
    done
    
    for loop in 1234
    do echo "${loop}"
    done
    
    for loop in "this is shell,enjoy it"
    do echo "${loop}"
    done
    
    for loop in "this is shell,enjoy it" "java is no.1"
    do echo "${loop}"
    done
    
    for file in ./*
    
    do
    if test -x ${file}
    then
            echo "${file} can execute"
    else
            echo "${file} can not execute"
    fi
    
    done

root@VM-0-17-ubuntu:/home/bash# ./bash19.sh
    每次输出的内容根据空格作为分割
    this is 1
    this is 2
    this is 3
    this is 4
    this is 5
    1234
    this is shell,enjoy it
    this is shell,enjoy it
    java is no.1
    ./bash01.sh can execute
    ./bash02.sh can execute
    ./bash03.sh can execute
    ./bash04.sh can execute
    ./bash05.sh can execute
    ./bash06.sh can execute
    ./bash07.sh can execute
    ./bash08.sh can execute
    ./bash09.sh can execute
    ./bash10.sh can execute
    ./bash11.sh can execute
    ./bash12.sh can execute
    ./bash13.sh can execute
    ./bash14.sh can execute
    ./bash15.sh can execute
    ./bash16.sh can execute
    ./bash17.sh can execute
    ./bash18.sh can execute
    ./bash19.sh can execute
    ./file1.txt can not execute
    ./file2.txt can not execute

**while循环**

echo "type ctrl+d to exit"
    echo "please enter ur favourite game"
    while read gameName
    do
            echo "wow,it is ${gameName}"
    done

root@VM-0-17-ubuntu:/home/bash# ./bash21.sh
    type ctrl+d to exit
    please enter ur favourite game
    lol
    wow,it is lol

count=0
    while [[ ${count} -lt  5 ]]
    do
            echo ${count}
            count=$(expr ${count} + 1)
    done

root@VM-0-17-ubuntu:/home/bash# ./bash20.sh
    0
    1
    2
    3
    4

**until循环**

a=0
    until [[ ${a} -gt 10 ]]
    do
            echo ${a}
            a=$(expr ${a} + 1)
    done

root@VM-0-17-ubuntu:/home/bash# ./bash22.sh
    0
    1
    2
    3
    4
    5
    6
    7
    8
    9
    10