Java调用linux指令工具类，直接执行cmd，执行grep指令返回结果，执行sed追加指令，hdfs下载指令，获取文件行数

问题背景LinuxUtils工具类Lyric：梦想挟带眼泪

有时候会操作linux指令读取或修改文件，封装一个常用的Linux工具类比较方便

1 LinuxUtils工具类

package com.yg.util;

import lombok.extern.slf4j.Slf4j;

import java.io.BufferedReader;
import java.io.IOException;
import java.io.InputStreamReader;
import java.io.LineNumberReader;


@Slf4j
public class LinuxUtils {


    public static boolean downloadHdfsFile(String hdfsPath, String outputPath) {
        String cmd = "hdfs dfs -cat " + hdfsPath + "
    public static String getCmdResult(String cmd) {

        String result = "";
        try {

            Process process = Runtime.getRuntime().exec(cmd);
            InputStreamReader ir = new InputStreamReader(process.getInputStream());
            LineNumberReader input = new LineNumberReader(ir);
            String line;
            while ((line = input.readLine()) != null) {
                result = line;
            }

        } catch (IOException e) {
            System.err.println("IOException " + e.getMessage());
        }
        return result;
    }

    
    public static String getGrepCmdReturn(String cmdStr) {

        String[] cmd = new String[3];

        cmd[0] = "/bin/sh";
        cmd[1] = "-c";
        cmd[2] = cmdStr;

        //得到Java进程的相关Runtime运行对象
        Runtime runtime = Runtime.getRuntime();
        StringBuffer stringBuffer = null;
        try {

            Process process = runtime.exec(cmd);

            BufferedReader bufferReader = new BufferedReader(
                    new InputStreamReader(process.getInputStream()));

            stringBuffer = new StringBuffer();

            String temp = null;

            while ((temp = bufferReader.readLine()) != null) {
                stringBuffer.append(temp);
            }


        } catch (IOException e) {
            e.printStackTrace();
        }

        return stringBuffer.toString();
    }

    public static int getFileRows(String path) {
        FileReader in;
        int rows = 0;
        try {
            in = new FileReader(path);
            LineNumberReader reader = new LineNumberReader(in);
            reader.skip(Long.MAX_VALUE);
            rows = reader.getLineNumber();
            reader.close();
        } catch (Exception e) {
            e.printStackTrace();
        }
        return rows;
    }

    public static void main(String[] args) {

        System.out.println(LinuxCmdUtils.getGrepCmdReturn("dmidecode -s system-serial-number|grep -v "#""));
    }
}

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