Several small shell program

Explanation

GitHub Address: HTTPS : //github.com/ouyangsuo/SimpleShellDemos
The following shell script, to the system after the completion of all copies of the public directory executable program, so that the directory can be performed in any

sudo cp hello calc mcp fileinfo guessnum /bin/

HelloShell (/ bin in / Hello)

#!/bin/bash
#↑声明shell解释器位置

word="Hello Shell"
echo "Hello Shell!"

Math (/ / bin in the calculated value)

#!/bin/bash
# calc --add 3 4 执行结果为7

#第一个参数为--add时，做加法
if [[ $1 = "--add" ]];then
echo --add
echo $(($2+$3))

#第一个参数为--sub时，做减法
elif [[ $1 = "--sub" ]];then
echo --sub
echo $(($2-$3))

#第一个参数为--mul时，做乘法
elif [[ $1 = "--mul" ]];then
echo --mul
echo $(($2*$3))

#第一个参数为--div时，做除法
elif [[ $1 = "--div" ]];then
echo --div
echo $(($2/$3))

#第一个参数为--div时，做求余
elif [[ $1 = "--mod" ]];then
echo --mod
echo $(($2%$3))

#第一个参数为其它时，提示错误
else
echo $1
echo fuck off,不支持的操作符
fi

Display information file (/ bin in / FileInfo a)

#!/bin/bash
#fileinfo ~/hello 显示该文件的权限和内容

fileinfo(){


    # 如果文件不存在，报错退出
    if [[ ! -e $1 ]];then
        echo "$1 doesn't exist!"
        return 0
    fi

    echo $1:

    #判断和输出文件的读写执行权限
    if [[ -r $1 ]];then
        echo -n "readable,"
    else
        echo -n "NOT-readble,"
    fi

    if [[ -w $1 ]];then
        echo -n "writable,"
    else
        echo -n "NOT-writable,"
    fi

    if [[ -x $1 ]];then
        echo "executable"
    else
        echo "NOT-executable"
    fi

    #通过Linux的标准命令，输出文件内容
    echo -e "\ncontents":
    echo ====================
    cat $1
    echo ====================

}

# 调用函数,传入文件位置参数
fileinfo $1

File copy from the definition (/ bin in / MCP)

#!/bin/bash
#用户通过mcp srcfile dstfile实现拷贝
#通过mcp -a srcfile dstfile实现追加
#拷贝完成后询问用户是否立即查看

docp(){

#判断是新建还是追加
append=0
if [[ $1 = "-a" ]];then
    append=1
    srcfile=$2
    dstfile=$3
else
    append=0
    srcfile=$1
    dstfile=$2
fi
echo "srcfile:$srcfile,dstfile:$dstfile"

#判断源文件是否存在
if [[ ! -e $srcfile ]];then
    echo "stupid! souce file does not exist!"
    return 0
fi

#如果目标文件不存在则创建
if [[ ! -e $dstfile ]];then
    touch $dstfile
fi

#写入文件
if [[ $append -eq 1 ]];then
    cat < $srcfile >> $dstfile
else
    cat < $srcfile > $dstfile
fi

#询问用户是否要查看目标文件
echo -n "$srcfile written to $dstfile successfully! read it now?[y/n]:"
read temp
if [[ $temp = 'y' ]];then
    echo "content:"
    echo ====================
    cat < $dstfile
    echo ====================
fi

}

#调用函数，传入参数
docp $1 $2 $3

Small game viewing (/ bin in / guessnum)

#!/bin/bash

#生成随机数，此处的rand命令需要安装一下
answer=`rand --max 1000`
#answer=$(cat /dev/urandom | head -n 10 | cksum | awk -F ' ' '{print $1}')
#answer=$(($answer%1000))
echo $answer

while true
do
    #提示用户输入
    echo -n "please enter a num between 0~1000:"
    read guess

    #看答案
    if [[ $guess = "drop it" ]];then
        echo "the answer is:$answer"
        break
    fi

    #对比
    if [[ $guess -eq $answer ]];then
        echo "bingo!the answer is:$answer"
        break
    elif [[ $guess -gt $answer ]];then
        echo "too big!"
    else    
        echo "too small!"       
    fi
done

echo "GAME OVER!"

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Pang Wen

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