linux,windows,sockets,network-programming,raspberry-pi , Java read bytes from Socket on Linux

Java read bytes from Socket on Linux


Tag: linux,windows,sockets,network-programming,raspberry-pi

I'm trying to send a file from my Windows machine to my Raspberry-Pi 2, and I have a client and a server. The client should be able to send a zip file over the network to my server on my linux machine. I know my client and server work on Windows, as when I run both the client and server on windows and connect using it works perfectly. But when sending it to my Pi, nothing gets sent over the socket. Any suggestion?

    package zipsd;


    public class Main {
        public static void main(String[] args) throws Exception {
            if (args.length < 3)
                System.out.println("Usage: zipsd <port> <directory> <password>");
            else {
                int port = Integer.parseInt(args[0]);
                String directory = args[1];
                String password = args[2];

                System.out.println("zipsd: starting server on port " + port);
                System.out.println("zipsd: directory = " + directory);

                ServerSocket ss = new ServerSocket(port);

                System.out.println("zipsd: listening...");

                while (true) {
                    try {
                        Socket client = ss.accept();

                                .println("zipsd: from " + client.getInetAddress());

                        InputStream input = client.getInputStream();
                        BufferedReader in = new BufferedReader(
                                new InputStreamReader(input));
                        PrintStream out = new PrintStream(client.getOutputStream());

                        String pwdAttempt = in.readLine();

                        if (pwdAttempt != null) {

                            if (!pwdAttempt.equals(password)) {
                                out.println("[SERVER] zipsd: invalid password");
                            } else {
                                out.println("[SERVER] zipsd: authenticated");

                                String zipName = in.readLine();
                                if (zipName != null) {
                                    File zipFile = new File(directory + "/"
                                            + zipName);

                                    try {
                                        FileOutputStream fos = new FileOutputStream(
                                        BufferedOutputStream bos = new BufferedOutputStream(

                                        byte[] data = new byte[1024 * 1024 * 50];
                                        int count;

                                        while((count = > 0)
                                            bos.write(data, 0, count);

                                        for(int i = 0; i < 200; i++) //to see if data gets sent, it just prints 0's :(

                                        System.out.println("Got zip file " + zipName);



                                    } catch (Exception e) {
                                        out.println("[SERVER] zipsd: error in transfer.");
                    } catch (Exception e) {


    package zipsend;

import java.nio.file.Files;

public class Main {

    public static class ZipUtils {

        public static void zipFolder(final File folder, final File zipFile)
                throws IOException {
            zipFolder(folder, new FileOutputStream(zipFile));

        public static void zipFolder(final File folder,
                final OutputStream outputStream) throws IOException {
            try (ZipOutputStream zipOutputStream = new ZipOutputStream(
                    outputStream)) {
                processFolder(folder, zipOutputStream, folder.getPath()
                        .length() + 1);


        private static void processFolder(final File folder,
                final ZipOutputStream zipOutputStream, final int prefixLength)
                throws IOException {
            for (final File file : folder.listFiles()) {
                if (file.isFile()) {
                    final ZipEntry zipEntry = new ZipEntry(file.getPath()
                    try (FileInputStream inputStream = new FileInputStream(file)) {
                        byte[] buf = new byte[(int) file.length() + 1];
                        int read = 0;
                        while ((read = != -1) {
                            zipOutputStream.write(buf, 0, read);

                } else if (file.isDirectory()) {
                    processFolder(file, zipOutputStream, prefixLength);

    public static void main(String[] args) throws Exception {
        if(args.length < 4)
            System.out.println("Usage: zipsend <folder> <ip> <port> <password>");
        else {
            String toZip = args[0];
            String ip = args[1];
            int port = Integer.parseInt(args[2]);
            String pwd = args[3];

            File folderToZip = new File(toZip);
            if(!folderToZip.exists()) {
                System.out.println("[ERROR] invalid folder name");

            System.out.print("[INFO] connecting... ");

            Socket s = new Socket(ip, port);

            System.out.println("[INFO] authenticating... ");

            BufferedReader in = new BufferedReader(new InputStreamReader(s.getInputStream()));
            PrintStream out = new PrintStream(s.getOutputStream());


            System.out.print("[INFO] zipping " + toZip + "... ");

            File zipFile = new File(System.getProperty("user.dir") + "\\" +  folderToZip.getName() + ".zip");

            ZipOutputStream zout = new ZipOutputStream(new FileOutputStream(zipFile));
            ZipUtils.processFolder(folderToZip, zout, folderToZip.getPath().length() + 1);


            //Transfer file


            byte[] data = new byte[(int)zipFile.length()];
            FileInputStream fis = new FileInputStream(zipFile);
            BufferedInputStream bis = new BufferedInputStream(fis);

            System.out.println("[INFO] sending zip file... ");
            OutputStream os = s.getOutputStream();

            int count;
            while((count = > 0) {
                os.write(data, 0, count);


            System.out.println("[INFO] done. Sent " + Files.size(zipFile.toPath()) + " bytes.");


InputStream input = client.getInputStream();
BufferedReader in = new BufferedReader(new InputStreamReader(input));

Your problem is here. You can't use multiple inputs on a socket when one or more of them is buffered. The buffered input stream/reader will read-ahead and 'steal' data from the other stream. You need to change your protocol so you can use the same stream for the life of the socket at both ends. For example, use DataInputStream, with readUTF() for the file name and read() for the data: at the sender, use DataOutputStream, with writeUTF() for the filename and write() for the data.


AWK write to new column base on if else of other column

I have a CSV file with columns A,B,C,D. Column D contains values on a scale of 0 to 1. I want to use AWK to write to a new column E base in values in column D. For example: if value in column D <0.7, value in column E =...

What is the max length of a share path in windows?

As I read in the MSDN site, for example, the maximum path on drive D is "D:\some 256-character path string" where "" represents the invisible terminating null character for the current system codepage. But when I was created a share with a long path (more than 100 symbols) they trim...

sys.argv in a windows environment

I'm attempting to learn python using the book 'a byte of python'. The code: import sys print('the command line arguments are:') for i in sys.argv: print(i) print('\n\nThe PYTHONPATH is', sys.path, '\n') outputs: the command line arguments are: C:/Users/user/PycharmProjects/helloWorld/ The PYTHONPATH is ['C:\\Users\\user\\PycharmProjects\\helloWorld', 'C:\\Users\\user\\PycharmProjects\\helloWorld', 'C:\\Python34\\', 'C:\\Python34\\DLLs', 'C:\\Python34\\lib', 'C:\\Python34', 'C:\\Python34\\lib\\site-packages']...

UAC error while installing Xampp 1.8.35 on windows 8

I am trying to install xampp but before installation it gives me the following error: I have disabled UAC and it gives me this error.When I press ok and install the thing anyway it still won't let start apache and my sql up. Also installation was done in Program file...

How to extract single-/multiline regex-matching items from an unpredictably formatted file and put each one in a single line into output file?

I have a very huge file which looks like this: <a>text</a>text blah <b>data1</b>abc<b>data2</b> <b>data3</b>blahblah <c>text</c> <d>text</d> <x>blahblah<b>data4 data5 data6</b> <b>data7 </x> That is, its formatting is unpredictable. I need to extract each <b>...</b> item (it might contain multiline text!) and put every one of them in a single separate line....

Extra backslash when storing grep in a value

In a bash script I have: Check="grep -e '"'\(-S mount\)'"' /etc/audit/audit.rules" set -x When you run it it shows it as: CHECK='grep -e '\''\(-S mount\)'\'' /etc/audit/audit.rules' Now it works exactly what I want but I want to understand it. Why is there 2 extra \'s?...

What does it indicate if /proc/PID/maps shows zero for all addresses?

I'm debugging a problem with a Linux DNS server. Curiously, when I look at /proc/PID/maps for the DNS server process, this is what I get: 00000000-00000000 r-xp 00000000 00:0e 2344 /usr/sbin/unbound 00000000-00000000 rw-p 00000000 00:0e 2344 /usr/sbin/unbound 00000000-00000000 ---p 00000000 00:00 0 00000000-00000000 rw-p 00000000 00:00 0 [heap] 00000000-00000000 rw-p...

Execute a batch file before executing in a shortcut (.lnk)

I have multiple versions of a program called Siemens NX. NX uses environmental variables for configuration. I need NX 10.0 to use a different set of environmental variables than my NX 7.5 which uses the system environmental variables. Therefore, I have written a batch file that setups the environmental variables...

String manipulation with batch scripting

I need to save the variable in %%c temporarily which comes from a for loop. But when I try to do that, the content changes unexpectedly. Some space characters appear at the end of the string. The content of %%c is a.jpg by the way. echo %%ca REM prints a.jpga...

Get system startup time (without reading /proc/uptime)

I cannot open /proc/uptime due to open_basedir restriction. The command uptime is too old and doesn't have the -s flag support. How can I - in PHP - get time when the server started? My current code is this, but it does not work on the production server (for the...

Syncing Vagrant VMs across different physical servers

I'm using Vagrant to deploy my VMs and my current setup looks like this: server1 = VM1, VM2, VM3 ( main production server ) server2 = VM1, VM2, VM3 ( backup server ) My questions is, can I somehow sync the VMs across the different physical servers in case one...

What are correct permissions for Linux Apache2 PHP 5.3 log file?

I discovered the reason why I was not getting entries into my php_errors.log file related to permissions. Right now, I have set it to 666 (rw-rw-rw-) but surely this is a security weakness? Thus, my question. php.ini file: error_log /var/log/httpd/php_errors.log log_errors On # ls -ld /var/log /var/log/httpd /var/log/httpd/php_errors.log drwxr-xr-x 6...

Listing directories by content size using C# [closed]

I'm trying to list all folders of my c drive excluding the document folder which i do not seem to have access to. This first seemed rather simple to me but i found myself still struggling with it despite the seemingly rich .net library. I can't post any code as...

Should I use different WSAOVERLAPPED struct for WSASend and WSARecv?

I'm developing a server-client application using WinSock. Does using the same WSAOVERLAPPED with both WSASend and WSARecv works well? Should I use different WSAOVERLAPPED struct for WSASend and WSARecv?...

Would using Vagrant be overkill? [on hold]

I'm a developer-hobbyist running Windows 8.1 on a Yoga 2 Pro. I mostly do Python/Django work but I think I'm gonna pick up Ruby soon. The thing is, Windows always seems to be the limiting factor for any project I want to pick up. Last time I tried to install...

How to send Ctrl+S through SendKeys.Send() method to save a file(save as dialog)

I need to save a file which is in an External application using SendKeys.Send() method. The keys needed to be sent are Ctrl+S. I wrote the below code, but its not working: SendKeys.SendWait("^%s?"); // to get the Save As dialog Thread.Sleep(5000); SetForegroundWindow(FindWindow(null, "Save As")); Thread.Sleep(5000); SendKeys.SendWait("xyz"); // Sending FileName ...

Application is missing required files

Pic of Error: Cannot Download the Application. The Application is missing required Files. Contact Application Vendor For Assistance. So I'm building a windows form application using SharpDevelop 5.2 and I'm trying to make a standalone/version someone else would be able to use on another machine. In sharpdevelop (and visual...

Apache - finding configuration file path

I have to migrate another apache instance from 2.2 to 2.4 but I have one problem. In Apache monitor I see multiple services running but I don't really know where apache .conf files are stored. In previous migrations from 2.2 to 2.4 I had them somewhere within conf folder. Apache...

Force linux to use php as php55

Helllo, I have a little problem here. I have PHP 5.3 installed and it's accessible via php command, I also have php 5.5 accessible as php55 command. Now I need to force linux to use php55 when I write php command. Simple way: How I switch the versions of php?...

Linux - sh script - download multiple files from FTP

I need script that can download files from ftp via my sh code I have use expect with ftp, but if I do for loop inside code, I got wrong # args: should be "for start test next command" while executing "for v in "a b c"" My code /usr/bin/expect...

sed string with special character New

when i use this script to replace : by sed -i -e "s/" config.xml i have the error : sed: -e expression n°1, caractère 41: option inconnue pour `s' can anyone help me thanks in advance regard, Youssef...

How to append entry the end of a multi-line entry using any of stream editors like sed or awk

I am trying to use a script to append the host name at the end of a multi-line entry of a specific Host_Alias field in sudoers file. The current sudoers file has an entry similar to : Host_Alias srv_linuxestate= \ host10,host12,host13,host1,host50,\ host16,host1,host2,host11,host15,host21,\ host3,host14 My required output would be something like...

AWK count number of times a term appear with respect to other columns

Given a CSV file: id, fruit, binary 1, apple, 1 2, orange, 0 3, pear, 1 4, apple, 0 5, peach, 0 6, apple, 1 How can i calculate for each unique values in fruit, the number of times the binary value =1 / number of occurences of that fruit...

While loop in bash using variable from txt file

I am new to bash and writing a script to read variables that is stored on each line of a text file (there are thousands of these variables). So I tried to write a script that would read the lines and automatically output the solution to the screen and save...

Why doesn't “go get…” work while “go get…” OK?

I try to use go get to install pool according to, but can't success: C:\Users\xiaona\Documents\GitHub> go get -v Fetching https fetch failed. Fetching import "": http/https fetch: Get l.v2?go-get=1: dial tcp ConnectEx tcp: A connection attempt failed because the connected party did not...

NASM: copying a pointer from a register to a buffer in .data

I am new to asm. I am trying to copy a pointer from a register to a .data variable using NASM, on linux 64-bit. Concider this program: section .data ptr: dq 0 section .text global _start _start: mov [ptr], rsp mov rax, 60 mov rdi, 0 syscall Here I try...

make error during building webkitgtk

I use UBuntu 14.04 LTS. I need to build webkitgtk 2.8.3 Here is an example instruction which I have used: linuxfromscratch When I run sudo make -j8 I get following log: Scanning dependencies of target JavaScriptCore-4-gir Scanning dependencies of target fake-generated-webkitdom-headers [ 0%] Scanning dependencies of target WebKit2-fake-api-headers Scanning dependencies...

fread(), solaris to unix portability and use of uninitialised values

Valgrind found the following error and I, after reading the documentation, the code and other questions in here couldn't figure it out why. Valgrind: first warning ~$ valgrind --vgdb=yes --vgdb-error=0 --read-var-info=yes --leak-check=yes --track-origins=yes debitadmin* debitadmin ==20720== Conditional jump or move depends on uninitialised value(s) ==20720== at 0x4013BC6: initialise (dbg.c:199) ==20720==...

How to set the classpath in Windows Command Line correctly

I have made many attempts to enter a command to run a JAR file correctly from the terminal, and I am 100% sure that all the JAR files and such are in the given paths, but I keep getting a ClassDefNotFoundException. Does it have anything to do with the way...

String parsing with batch scripting

I have a file called pictures.xml and it contains some pictures information like: <ResourcePicture Name="a.jpg"> <GeneratedPicture Name="b.jpg"/> <GeneratedPicture Name="c.jpg"/> </ResourcePicture> <ResourcePicture Name="z1.jpg"> <GeneratedPicture Name="z2.jpg"/> <GeneratedPicture Name="z3.jpg"/> <GeneratedPicture Name="z4.jpg"/> </ResourcePicture> What I want do do is to get each line in for loop and print the names of the pictures. Sample...

I cannot use the msg command in cmd (or batch for that matter). How can I fix this?

While in cmd or making a batch file, I cannot use the command msg. When I try to use it, it returns the error msg is not recognized as an internal or external command, operable program or batch file." I'm pretty sure the error is that im missing a msg.exe...

Ignore first few lines and last few lines in a file Linux

I have a file like this and would like to print $0 except the first two and last three lines in linux. Tried awk command but no luck, is there any options I am using the following command - I suppose I am doing something wrong, but not able to...

Parsing the text file line-by-line using batch script (batch file)

So, I am programming in the batch script and I came across this issue. The following code will take yourwords.txt file and parse it. The existedWord variable will have the last word of the text file. So, everytime when I run this program it will only compare the user's input...

How does the kernel separate threads from processes

Suppose I have a browser process like Firefox, that has pid = 123. Firefox has 5 opened tabs each running in a separate thread, so in total it has 5 threads. So I want to know in depth, how the kernel will separate the process into the thread to execute...

Django MySQLClient pip compile failure on Linux

Django documentation as of v1.8 recommends using mysqlclient connector for the framework. I'm attempting to pip install the package on Ubuntu 14.04 with Python 3.4 and running into a GCC error that I'm unable to find reference to. I'm not an expert on compiling software, so was hoping somebody can...

how to modify an array value with given index?

I want to modify an array cell, which I can do when I know the cell as a number. However here my cell position is given by $i. pomme[`${i}`]="" I tried without the `` and it doesn't work either? How am I suppose to do it?...

Linux-wget command

I need a quick help on customizing my wget command in a shell script: The wget command looks something like this: wget http://infamvn:8081/nexus/content/groups/LDM_REPO_LIN64/com/infa/com.infa. products.ldm.ingestion.server.scala/ Here I'd like to add the in a variable, so I created a script something like this: n = wget...

Why does Windows Server 2008 think Italy should be in W. European Time?

Why does MS Windows (specifically server 2008 here) consider Italy to be in W. European Time when (I think) it should be in Central European Time according to every other source I can find? TZUtil /g gives: W. Europe Standard Time The control panel shows: (UTC+01:00) Amsterdam, Berlin, Bern, Rome,...

Java read bytes from Socket on Linux

I'm trying to send a file from my Windows machine to my Raspberry-Pi 2, and I have a client and a server. The client should be able to send a zip file over the network to my server on my linux machine. I know my client and server work on...

Delete some lines from text using Linux command

I know how to match text using regex patterns but not how to manipulate them. I have used grep to match and extract lines from a text file, but I want to remove those lines from the text. How can I achieve this without having to write a python or...

linux running command as root from c code that run as normal user

I have a c++ code and I need to running from it a command to adjust the system time. so I thought using system("su root -c date hh:mm") command from my c++ code. The problem is that when I write 'su root -c date hh:mm' in the terminal its requires...

bat file script to check if string contains other string

I need to write a batch file that will check if a variable contains specific value. I tried to do the following: If "%%a"=="%%a:%pattern%" ( echo Yes ) else ( echo No ) input example: %%a="bob binson" %patern%="binson" I never get Yes printed! can anyone please tell what i missed...

ret_from_syscall source code and when it is called

In the below call trace we see function called ret_from_syscall. Which function is this ? When it will called during system call ? Where is the corresponding code for this ? May 7 16:40:34.322086 warn TCU-0 kernel: [cf83ddc0] [00009751] 0x9751 (unreliable) May 7 16:40:34.322086 warn TCU-0 kernel: [cf83ddd0] [c00469ac] do_syslog+0x198/0x424...

Unable to edit netbeans.conf

I am trying to modify 'netbeans.conf' located at following path: C:\Program Files\NetBeans 8.0.2\etc When i modify the file; add -J-Dfile.encoding=UTF-8 In Notepad, it is not allowing me to save the original file. In Notepad++, it says 'please echeck if this file is opened in another program'. Netbeans is installed in...

How can I resolve the “Could not fix timestamps in …” “…Error: The requested feature is not implemented.”

I have been trying to build a project in F# on Linux that I have located here on github. It's a basic kata project that I am working on as a demo. However on Linux (specifically Ubuntu 14.04 LTS Desktop) I haven't been able to get it to build yet...

sed and PHP tags

I have a problem using SED. I have a php file whit this structure in the very first line: <?php echo 'first' ?><?php echo 'second' ?><?php echo 'third';?> I'm trying to remove the first two statements and have as a result: <?php echo 'third';?> I've tried this code: sed -i...

Using an ad-hoc libc with a tool which is an argument of another tool

I need to use a particular libc to run a tool (cp). The problem is that this tool has to be used as argument of another tool (for example timeout) and I don't want to use the modified libc with this one. I tried to do: timeout 10 LD_LIBRARY_PATH=/path/to/mod/libc/ cp...

Bash modify CSV to change a field

I have a very big CSV file (aprox. 10.000 rows and 400 columns) and I need to modify certain columns (like 15, 156, 220) to change format from 20140321132233 to 2014-03-21 13:22:33. All fields that I need to modify are datetime. I saw some examples using awk but for math...

Override .gitattributes text=auto in Windows

This is pretty unintuitive: C:\python-tdl\examples\termbox>git config core.autocrlf false C:\python-tdl\examples\termbox>git commit warning: LF will be replaced by CRLF in examples/termbox/ The file will have its original line endings in your working directory. warning: LF will be replaced by CRLF in examples/termbox/ The file will have its original line endings in...