I have to send email from a Linux server through a Java program. When I run the command on SSH Secure Shell, everything is fine. But when I call the same command from Java, the subject after space is removed.
Script is as follows:
mail -s "This is a test subject" "receiver#example.com"
When I execute the above script through Java, the subject is truncated to "This (Double quotes followed by the first word)
Java code for running the above script is:
Runtime.getRuntime().exec(emailCommand);
*Here emailCommand refers to the shell script.
Did a lot of googling but did not find a solution.
After the discussion with I am providing you a solution like below:-
String[] command ={"/path/to/your/shellscript.sh", "shellscriptcommandlineparameter"};
ProcessBuilder pb = new ProcessBuilder(command);
pb.redirectOutput(new File("/tmp/output.txt"));
try {
Process p = pb.start();
p.waitFor();
} catch (InterruptedException e) {
e.printStackTrace();
}catch (Exception e1) {
e1.printStackTrace();
}
}
Try with this updated java code and you can see the output from your shell script in output.txt file.
I'm writing a plugin in order to restart a server application on Linux (though I'm testing on OSX). The way I'm doing this is using a shell script which commands the application to stop, and then oversees the death of the process, safely starting a new one when the time comes.
My script works when I execute it manually from the command line. However, when I execute it from within the application, the shell process is killed along with the application.
I've tried two different methods of running the process from Java:
String scriptArgs[] = {"sh", "restart.sh", "&"};
try {
Runtime.getRuntime().exec(scriptArgs);
} catch (IOException e) {
e.printStackTrace();
}
and
ProcessBuilder processBuilder = new ProcessBuilder("sh", "restart.sh");
try {
processBuilder.directory(new File(System.getProperty("user.dir")));
processBuilder.redirectErrorStream(false);
processBuilder.start();
} catch (IOException e) {
e.printStackTrace();
}
Both of these methods gave the same result: the script was called, it successfully shut down the application, and then it died before it could continue. Is there any method to start a completely independent process from Java?
When you run a process from java you are creating a shell instance which then runs the process. The shell will only exit once this process has finished even if it is being run in the background &
To run a process in headless mode you need to use the nohup command. For details, see here.
A usage could look like this:
ProcessBuilder processBuilder = new ProcessBuilder("nohup", "sh", "restart.sh");
try {
processBuilder.directory(new File(System.getProperty("user.dir")));
processBuilder.redirectErrorStream(false);
processBuilder.start();
} catch (IOException e) {
e.printStackTrace();
}
In my Java application, I want to run a batch file that calls "scons -Q implicit-deps-changed build\file_load_type export\file_load_type"
It seems that I can't even get my batch file to execute. I'm out of ideas.
This is what I have in Java:
Runtime.
getRuntime().
exec("build.bat", null, new File("."));
Previously, I had a Python Sconscript file that I wanted to run but since that didn't work I decided I would call the script via a batch file but that method has not been successful as of yet.
Batch files are not an executable. They need an application to run them (i.e. cmd).
On UNIX, the script file has shebang (#!) at the start of a file to specify the program that executes it. Double-clicking in Windows is performed by Windows Explorer. CreateProcess does not know anything about that.
Runtime.
getRuntime().
exec("cmd /c start \"\" build.bat");
Note: With the start \"\" command, a separate command window will be opened with a blank title and any output from the batch file will be displayed there. It should also work with just `cmd /c build.bat", in which case the output can be read from the sub-process in Java if desired.
Sometimes the thread execution process time is higher than JVM thread waiting process time, it use to happen when the process you're invoking takes some time to be processed, use the waitFor() command as follows:
try{
Process p = Runtime.getRuntime().exec("file location here, don't forget using / instead of \\ to make it interoperable");
p.waitFor();
}catch( IOException ex ){
//Validate the case the file can't be accesed (not enought permissions)
}catch( InterruptedException ex ){
//Validate the case the process is being stopped by some external situation
}
This way the JVM will stop until the process you're invoking is done before it continue with the thread execution stack.
Runtime runtime = Runtime.getRuntime();
try {
Process p1 = runtime.exec("cmd /c start D:\\temp\\a.bat");
InputStream is = p1.getInputStream();
int i = 0;
while( (i = is.read() ) != -1) {
System.out.print((char)i);
}
} catch(IOException ioException) {
System.out.println(ioException.getMessage() );
}
ProcessBuilder is the Java 5/6 way to run external processes.
To run batch files using java if that's you're talking about...
String path="cmd /c start d:\\sample\\sample.bat";
Runtime rn=Runtime.getRuntime();
Process pr=rn.exec(path);`
This should do it.
The executable used to run batch scripts is cmd.exe which uses the /c flag to specify the name of the batch file to run:
Runtime.getRuntime().exec(new String[]{"cmd.exe", "/c", "build.bat"});
Theoretically you should also be able to run Scons in this manner, though I haven't tested this:
Runtime.getRuntime().exec(new String[]{"scons", "-Q", "implicit-deps-changed", "build\file_load_type", "export\file_load_type"});
EDIT: Amara, you say that this isn't working. The error you listed is the error you'd get when running Java from a Cygwin terminal on a Windows box; is this what you're doing? The problem with that is that Windows and Cygwin have different paths, so the Windows version of Java won't find the scons executable on your Cygwin path. I can explain further if this turns out to be your problem.
Process p = Runtime.getRuntime().exec(
new String[]{"cmd", "/C", "orgreg.bat"},
null,
new File("D://TEST//home//libs//"));
tested with jdk1.5 and jdk1.6
This was working fine for me, hope it helps others too.
to get this i have struggled more days. :(
I had the same issue. However sometimes CMD failed to run my files.
That's why i create a temp.bat on my desktop, next this temp.bat is going to run my file, and next the temp file is going to be deleted.
I know this is a bigger code, however worked for me in 100% when even Runtime.getRuntime().exec() failed.
// creating a string for the Userprofile (either C:\Admin or whatever)
String userprofile = System.getenv("USERPROFILE");
BufferedWriter writer = null;
try {
//create a temporary file
File logFile = new File(userprofile+"\\Desktop\\temp.bat");
writer = new BufferedWriter(new FileWriter(logFile));
// Here comes the lines for the batch file!
// First line is #echo off
// Next line is the directory of our file
// Then we open our file in that directory and exit the cmd
// To seperate each line, please use \r\n
writer.write("cd %ProgramFiles(x86)%\\SOME_FOLDER \r\nstart xyz.bat \r\nexit");
} catch (Exception e) {
e.printStackTrace();
} finally {
try {
// Close the writer regardless of what happens...
writer.close();
} catch (Exception e) {
}
}
// running our temp.bat file
Runtime rt = Runtime.getRuntime();
try {
Process pr = rt.exec("cmd /c start \"\" \""+userprofile+"\\Desktop\\temp.bat" );
pr.getOutputStream().close();
} catch (IOException ex) {
Logger.getLogger(MainFrame.class.getName()).log(Level.SEVERE, null, ex);
}
// deleting our temp file
File databl = new File(userprofile+"\\Desktop\\temp.bat");
databl.delete();
The following is working fine:
String path="cmd /c start d:\\sample\\sample.bat";
Runtime rn=Runtime.getRuntime();
Process pr=rn.exec(path);
This code will execute two commands.bat that exist in the path C:/folders/folder.
Runtime.getRuntime().exec("cd C:/folders/folder & call commands.bat");
import java.io.IOException;
public class TestBatch {
public static void main(String[] args) {
{
try {
String[] command = {"cmd.exe", "/C", "Start", "C:\\temp\\runtest.bat"};
Process p = Runtime.getRuntime().exec(command);
} catch (IOException ex) {
}
}
}
}
To expand on #Isha's anwser you could just do the following to get the returned output (post-facto not in rea-ltime) of the script that was run:
try {
Process process = Runtime.getRuntime().exec("cmd /c start D:\\temp\\a.bat");
System.out.println(process.getText());
} catch(IOException e) {
e.printStackTrace();
}
I am building a Java application that calls a system command and executes that command before returning control to the Java thread. The debugging step that I have is that I have made a perl script called test.pl and I call that script from the Java method and in Windows I get the expected output and a return value of 0. In Linux I get no output or error output and I get a return value of 136. I have spent extensive time online trying to figure out where I have gone wrong but as I have said, on Windows it runs. I think it must be a simple error that I am just not catching.
Here is the code derived from the excellent Runtime.exec() tutorial at http://www.javaworld.com/jw-12-2000/jw-1229-traps.html
try {
FileOutputStream fos = new FileOutputStream("output/" + this.startPosition + ".txt");
Runtime rt = Runtime.getRuntime();
Process proc = rt.exec(new String[]{"perl", "/data/stat-positive-selection/thaddeus/treesim/chr2YRI/test.pl"});
//System.out.println(commandLine);
// any error message?
StreamGobbler errorGobbler = new
StreamGobbler(proc.getErrorStream(), "ERROR");
// any output?
StreamGobbler outputGobbler = new
StreamGobbler(proc.getInputStream(), "OUTPUT", fos);
// kick them off
errorGobbler.start();
outputGobbler.start();
// any error???
int exitVal = proc.waitFor();
System.out.println("ExitValue: " + exitVal);
fos.flush();
fos.close();
} catch (Throwable e){
e.printStackTrace();
}
}
I have figured it out and fixed the code
new exec call, the use of the shell and the path to perl are required
Process proc = rt.exec(new String[]{"/bin/bash", "-c", "/usr/bin/perl /data/stat-positive-selection/thaddeus/treesim/chr2YRI/test.pl"});
The differences between the old and new versions are:
you are running the command from a shell, and
you are specifying the full pathname of the "perl" command.
In fact, in this context there doesn't seem to be a great deal of point in running the command from a shell. (Hypothetically, your Perl application might depend on environment variables that are set during shell initialization. However, the same environment variables would normally be inherited by and then from the Java command's environment. So unless the Java command is being launched in a strange way, this scenario is ... unlikely.)
So I think the substantative difference1 is that you are using the full pathname for "perl" ... and you don't a subshell to do that.
So, in the interests of science ( :-) ) I suggest you try this:
Process proc = rt.exec(new String[]{
"/usr/bin/perl",
"/data/stat-positive-selection/thaddeus/treesim/chr2YRI/test.pl"});
1 - ... the difference that makes a difference
I replaced the whole Runtime.exec() structure with the Apache Commons Exec library. It fixed the problem I was having.
http://commons.apache.org/proper/commons-exec/tutorial.html
I have a simple shell script which looks like this:
R --vanilla<myMRjob.R
hadoop fs -get /output_03/ /home/user/Desktop/hdfs_output/
This shell script runs myMRjob.R, and gets the output from hdfs to local file system. It executes fine from terminal.
When i am trying to run shell script from java code, i am unable to launch the MapReduce job i.e. the first line isn't getting executed. While "hadoop fs -get .." line is running fine through Java code.
Java code which i used is:
import java.io.*;
public class Dtry {
public static void main(String[] args) {
File wd = new File("/home/dipesh/");
System.out.println("Working Directory: " +wd);
Process proc = null;
try {
proc = Runtime.getRuntime().exec("./Recomm.sh", null, wd);
} catch (Exception e) {
e.printStackTrace();
}
}
}
The reason behind this whole exercise is that i want to trigger and display the result of the myMRjob.R in JSP.
Please help!
The reason your shell script isn't running from the exec call is because shell scripts are really just text files and they aren't native executables. It is the shell (Bash) that knows how to interpret them. The exec call is expecting to find a native executable binary.
Adjust your Java like this in order to call the shell and have it run your script:
proc = Runtime.getRuntime().exec("/bin/bash Recomm.sh", null, wd);
When you called hadoop directly from Java, it is a native executable and that's why it worked.