echo -e " In ------ Out" 什么意思

这是一个 Linux 命令行中的输出语句，其中：

- `echo` 是一个命令，用于在终端输出文本。
- `-e` 是一个选项，用于启用转义字符的解释。
- `" In ------ Out"` 是要输出的文本内容，其中的 `\n` 表示换行。

因此，这个命令会输出以下内容：

 In ------ Out

其中，`In` 和 `Out` 之间有一条横线，表示这是一个表格的头部。

相关问题

stm32hc-sr04超声波测距

好的，针对您的问题，我可以给出以下步骤：

1. 配置超声波模块的引脚，将Trig引脚连接到STM32的一个GPIO输出引脚，将Echo引脚连接到STM32的一个GPIO输入引脚。
2. 在代码中初始化GPIO引脚，并设置Trig引脚为输出模式，Echo引脚为输入模式。
3. 在代码中循环执行以下操作：
a. 将Trig引脚输出高电平持续10us，然后拉低。
b. 等待Echo引脚输出高电平，并记录当前时间戳。
c. 等待Echo引脚输出低电平，并记录当前时间戳。
d. 计算时间差，即为超声波从发射到接收返回的时间。
e. 根据声速和时间差计算距离。

以下是示例代码：

#include "stm32f4xx.h"

#define TRIG_PIN GPIO_Pin_0
#define ECHO_PIN GPIO_Pin_1
#define TRIG_PORT GPIOA
#define ECHO_PORT GPIOA

void delay_us(uint32_t us) {
    uint32_t ticks = us * (SystemCoreClock / 1000000);
    while (ticks--);
}

float get_distance(void) {
    GPIO_ResetBits(TRIG_PORT, TRIG_PIN);
    delay_us(2);
    GPIO_SetBits(TRIG_PORT, TRIG_PIN);
    delay_us(10);
    GPIO_ResetBits(TRIG_PORT, TRIG_PIN);

    uint32_t start_time = 0, end_time = 0;
    while (!GPIO_ReadInputDataBit(ECHO_PORT, ECHO_PIN));
    start_time = SysTick->VAL;
    while (GPIO_ReadInputDataBit(ECHO_PORT, ECHO_PIN));
    end_time = SysTick->VAL;

    float distance = (float)(start_time - end_time) * 10 / (SystemCoreClock / 1000000) * 340 / 2;    return distance;
}

int main(void) {
    GPIO_InitTypeDef GPIO_InitStruct;

    RCC_AHB1PeriphClockCmd(RCC_AHB1Periph_GPIOA, ENABLE);

    GPIO_InitStruct.GPIO_Pin = TRIG_PIN;
    GPIO_InitStruct.GPIO_Mode = GPIO_Mode_OUT;
    GPIO_InitStruct.GPIO_OType = GPIO_OType_PP;
    GPIO_InitStruct.GPIO_Speed = GPIO_Speed_100MHz;
    GPIO_InitStruct.GPIO_PuPd = GPIO_PuPd_NOPULL;
    GPIO_Init(TRIG_PORT, &GPIO_InitStruct);

    GPIO_InitStruct.GPIO_Pin = ECHO_PIN;
    GPIO_InitStruct.GPIO_Mode = GPIO_Mode_IN;
    GPIO_InitStruct.GPIO_OType = GPIO_OType_PP;
    GPIO_InitStruct.GPIO_Speed = GPIO_Speed_100MHz;
    GPIO_InitStruct.GPIO_PuPd = GPIO_PuPd_NOPULL;
    GPIO_Init(ECHO_PORT, &GPIO_InitStruct);

    while (1) {
        float distance = get_distance();
        // do something with distance
    }
}

转c#写法：#!/bin/sh time_stamp=`date +%s` function CheckStop() { if [ $? -ne 0 ]; then echo "execute fail, error on line_no:"$1" exit!!!" exit fi } function GenEcdsaKey() { ec_param_file_path="/tmp/ec_param.pem."$time_stamp openssl ecparam -out $ec_param_file_path -name prime256v1 -genkey CheckStop $LINENO openssl genpkey -paramfile $ec_param_file_path -out $1 CheckStop $LINENO openssl pkey -in $1 -inform PEM -out $2 -outform PEM -pubout CheckStop $LINENO rm $ec_param_file_path echo "gen_ecdsa_key succ prikey_path:"$1" pubkey_path:"$2 } function GenEcdsaSign() { ec_sign_info_file="/tmp/ec_sign_info_file."$time_stamp ec_sign_info_sha256="/tmp/ec_sign_info_sha256."$time_stamp ec_binary_sign_file="/tmp/ec_binary_sign_file."$time_stamp echo -n "$1"_"$2" > $ec_sign_info_file openssl dgst -sha256 -binary -out $ec_sign_info_sha256 $ec_sign_info_file CheckStop $LINENO openssl pkeyutl -sign -in $ec_sign_info_sha256 -out $ec_binary_sign_file -inkey $3 -keyform PEM CheckStop $LINENO openssl base64 -e -in $ec_binary_sign_file -out $4 CheckStop $LINENO rm $ec_sign_info_file $ec_sign_info_sha256 $ec_binary_sign_file echo "gen_ecdsa_sign succ sign_file_path:"$4 } function VerifyEcdsaSign() { ec_sign_info_file="/tmp/ec_sign_info_file."$time_stamp ec_sign_info_sha256="/tmp/ec_sign_info_sha256."$time_stamp ec_binary_sign_file="/tmp/ec_binary_sign_file."$time_stamp echo -n "$1"_"$2" > $ec_sign_info_file openssl dgst -sha256 -binary -out $ec_sign_info_sha256 $ec_sign_info_file CheckStop $LINENO openssl base64 -d -in $4 -out $ec_binary_sign_file CheckStop $LINENO openssl pkeyutl -verify -in $ec_sign_info_sha256 -sigfile $ec_binary_sign_file -pubin -inkey $3 -keyform PEM rm $ec_sign_info_file $ec_sign_info_sha256 $ec_binary_sign_file } function Usage() { echo "Usage:" echo "mmiot_ecdsa_sign.sh gen_ecdsa_key <private_key_file_path> <public_key_file_path>" echo "mmiot_ecdsa_sign.sh gen_ecdsa_sign <product_id> <sn> <private_

这是一个 shell 脚本，可以转换成 C# 的代码实现。不过，你给出的代码并不完整，缺少了最后一行的内容，需要补充完整后才能进行转换。

假设最后一行的内容是 `key_file_path> <signature_file_path> <private_key_file_path> <public_key_file_path>"`，则可以将上述 shell 脚本转换成以下的 C# 代码：

using System;
using System.Diagnostics;
using System.IO;

class Program
{
    static void Main(string[] args)
    {
        string command = args[0];
        string privateKeyFilePath;
        string publicKeyFilePath;
        string productId;
        string sn;
        string signatureFilePath;
        string ecParamFilePath;
        string ecSignInfoFile;
        string ecSignInfoSha256;
        string ecBinarySignFile;

        switch (command)
        {
            case "gen_ecdsa_key":
                privateKeyFilePath = args[1];
                publicKeyFilePath = args[2];
                GenEcdsaKey(privateKeyFilePath, publicKeyFilePath);
                break;

            case "gen_ecdsa_sign":
                productId = args[1];
                sn = args[2];
                privateKeyFilePath = args[3];
                publicKeyFilePath = args[4];
                signatureFilePath = args[5];
                GenEcdsaSign(productId, sn, privateKeyFilePath, publicKeyFilePath, signatureFilePath);
                break;

            case "verify_ecdsa_sign":
                productId = args[1];
                sn = args[2];
                privateKeyFilePath = args[3];
                publicKeyFilePath = args[4];
                signatureFilePath = args[5];
                VerifyEcdsaSign(productId, sn, privateKeyFilePath, publicKeyFilePath, signatureFilePath);
                break;

            default:
                Console.WriteLine("Unknown command: " + command);
                break;
        }
    }

    static void GenEcdsaKey(string privateKeyFilePath, string publicKeyFilePath)
    {
        string ecParamFilePath = "/tmp/ec_param.pem." + GetTimestamp();
        ExecuteCommand("openssl", "ecparam -out " + ecParamFilePath + " -name prime256v1 -genkey");
        ExecuteCommand("openssl", "genpkey -paramfile " + ecParamFilePath + " -out " + privateKeyFilePath);
        ExecuteCommand("openssl", "pkey -in " + privateKeyFilePath + " -inform PEM -out " + publicKeyFilePath + " -outform PEM -pubout");
        File.Delete(ecParamFilePath);
        Console.WriteLine("gen_ecdsa_key succ prikey_path:" + privateKeyFilePath + " pubkey_path:" + publicKeyFilePath);
    }

    static void GenEcdsaSign(string productId, string sn, string privateKeyFilePath, string publicKeyFilePath, string signatureFilePath)
    {
        string ecSignInfoFile = "/tmp/ec_sign_info_file." + GetTimestamp();
        string ecSignInfoSha256 = "/tmp/ec_sign_info_sha256." + GetTimestamp();
        string ecBinarySignFile = "/tmp/ec_binary_sign_file." + GetTimestamp();
        string ecSignInfo = productId + "_" + sn;
        File.WriteAllText(ecSignInfoFile, ecSignInfo);
        ExecuteCommand("openssl", "dgst -sha256 -binary -out " + ecSignInfoSha256 + " " + ecSignInfoFile);
        ExecuteCommand("openssl", "pkeyutl -sign -in " + ecSignInfoSha256 + " -out " + ecBinarySignFile + " -inkey " + privateKeyFilePath + " -keyform PEM");
        ExecuteCommand("openssl", "base64 -e -in " + ecBinarySignFile + " -out " + signatureFilePath);
        File.Delete(ecSignInfoFile);
        File.Delete(ecSignInfoSha256);
        File.Delete(ecBinarySignFile);
        Console.WriteLine("gen_ecdsa_sign succ sign_file_path:" + signatureFilePath);
    }

    static void VerifyEcdsaSign(string productId, string sn, string privateKeyFilePath, string publicKeyFilePath, string signatureFilePath)
    {
        string ecSignInfoFile = "/tmp/ec_sign_info_file." + GetTimestamp();
        string ecSignInfoSha256 = "/tmp/ec_sign_info_sha256." + GetTimestamp();
        string ecBinarySignFile = "/tmp/ec_binary_sign_file." + GetTimestamp();
        string ecSignInfo = productId + "_" + sn;
        File.WriteAllText(ecSignInfoFile, ecSignInfo);
        ExecuteCommand("openssl", "dgst -sha256 -binary -out " + ecSignInfoSha256 + " " + ecSignInfoFile);
        ExecuteCommand("openssl", "base64 -d -in " + signatureFilePath + " -out " + ecBinarySignFile);
        ExecuteCommand("openssl", "pkeyutl -verify -in " + ecSignInfoSha256 + " -sigfile " + ecBinarySignFile + " -pubin -inkey " + publicKeyFilePath + " -keyform PEM");
        File.Delete(ecSignInfoFile);
        File.Delete(ecSignInfoSha256);
        File.Delete(ecBinarySignFile);
    }

    static void ExecuteCommand(string command, string arguments)
    {
        var process = new Process
        {
            StartInfo = new ProcessStartInfo
            {
                FileName = command,
                Arguments = arguments,
                RedirectStandardOutput = true,
                RedirectStandardError = true,
                UseShellExecute = false,
                CreateNoWindow = true,
            }
        };
        process.Start();
        process.WaitForExit();
        if (process.ExitCode != 0)
        {
            string errorMessage = process.StandardError.ReadToEnd();
            Console.WriteLine("execute fail, error on line_no:" + new StackTrace().GetFrame(1).GetFileLineNumber() + " exit!!!");
            Console.WriteLine(errorMessage);
            Environment.Exit(-1);
        }
    }

    static int GetTimestamp()
    {
        return (int)(DateTime.UtcNow - new DateTime(1970, 1, 1)).TotalSeconds;
    }
}

注意，这里的 C# 代码中，使用了 `Process` 类来执行命令行命令，并且对命令执行结果进行了判断。同时，在命令行命令中，如果出现了空格等特殊字符，需要使用引号将其包裹起来。