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Executing linux command from java using exec('command') method

I am trying to execute a Linux command from my java class using the method exec() from the Runtime class in this way:
public static String xxUtilInfoFile (String sPath , String sFileName) throws Exception
{
Runtime r = null;
Process p = null;
String line_value="";
String output_data="";
/*execute the process*/
r = Runtime.getRuntime();
p = r.exec("file -bi " + sPath + sFileName);
p.waitFor();
/*Return the standard error output*/
BufferedReader in=new BufferedReader(new InputStreamReader(p.getInputStream()));
output_data = in.readLine();
return output_data;
}
The Linux command I want to use is file -bi fileName and it runs well except in the case the fileName has blanks inside, and that is the point.
I've already tried to use double quotes and backslash (\) because this method runs in the Linux bash console, but it doesn't run if I pass it as an argument of exec method.
Could anyone help me to resolve this issue?

Perhaps, you should pass an array of Strings to the exec() method at line 9 of your code:
p = r.exec(new String[]{ "file", "-bi", sPath, sFileName});

Running a grep command using java Runtime api

I need to grep some text inside a list of files(file count is huge) in unix server and then list the file name in a web gui. So I decided best way to achieve this is by writing a unix command executer using Runtime.getRuntime().
Works fine for most of the unix command but facing this strange grep issue.
First of all code:
public class UnixCommandExecutor {
private static StringBuffer output = new StringBuffer();
public static String exec(String command) throws Exception{
Process process = null;
process = Runtime.getRuntime().exec(command);
BufferedReader stdErr = getBufferedReader(process.getErrorStream());
BufferedReader stdIn = getBufferedReader(process.getInputStream());
StringBuffer data = extractData(stdErr);
if (data.length() >= 1) {
System.out.println("Error: " +data.toString());
throw new Exception(data.toString());
}
data = extractData(stdIn);
if (data.length() >= 1) {
output = data;
System.out.println("Output: " +data.toString());
}
return output.toString();
}
private static BufferedReader getBufferedReader(InputStream stream) {
InputStreamReader inReader = new InputStreamReader(stream);
BufferedReader buffReader = new BufferedReader(inReader);
return buffReader;
}
private static StringBuffer extractData(BufferedReader reader)
throws IOException {
StringBuffer data = new StringBuffer();
String s = "";
while ((s = reader.readLine()) != null) {
data.append(s + "\n");
}
return data;
}
public StringBuffer getOutput() {
return output;
}
}
Now the call would be something like this:
String output = exec("find . -name blah");
This works fine and the result is perfect. Or any other unix command executes and provides the result properly.
But when grep command is used it gives a strange error:
String output = exec("grep -l executor *");
Error: grep: *: No such file or directory
This is strange, since if I run this command directly on unix it gives the desired result.
Also tried giving the file path something like,
String output = exec("grep -l executor /file/path/*");
even then the error is:
Error: grep: /file/path/*: No such file or directory
Any ideas? or any other better way to solve this?
Any suggestion is welcome.

The * is interpreted by the shell, not grep itself. So it doesn't work if you start grep from your Java program.
You can use grep with -r to make it search recursively, then use . for the current directory:
grep -lr executor .
To simulate the behaviour of the shell, just replace * with a space separated list of all files in the folder you want to search in. You can get the list of all files with:
StringBuilder str = new StringBuilder();
for (File f : new File("your folder").listFiles()) {
if (f.isFile()) {
str.append(' ').append(f.getPath());
}
}
Now just replace the * with the result of str.toString().

Opening exe with parameters in Java, don't understand parameters

I'm aware how to open an exe program with parameters in Java from finding the answer online. However my specific shortcut is a bit complicated for me to understand.
I'm trying to open a shortcut which has the following target:
C:\Windows\System32\javaw.exe -cp jts.jar;total.2012.jar -Dsun.java2d.noddraw=true -Dswing.boldMetal=false -Dsun.locale.formatasdefault=true -Xmx768M -XX:MaxPermSize=128M jclient/LoginFrame C:\Jts
In my program I've split up the location and what I think are the parameters. However when I run the program I get the error 'Could not create Java Virtual Machine, Program will Exit'. Can someone with a better understanding of whats going on explain what I might be doing wrong or point me in a direction where I can read up?
String location = "C:\\Windows\\System32\\javaw.exe";
String p1="-cp jts.jar;total.2012.jar";
String p2="-Dsun.java2d.noddraw=true";
String p3="-Dswing.boldMetal=false";
String p4="-Dsun.locale.formatasdefault=true";
String p5="-Xmx768M";
String p6="-XX:MaxPermSize=128M";
String p7="jclient/LoginFrame" ;
String p8 = "C:\\Jts";
try {
Process p = new ProcessBuilder(location,p1,p2,p3,p4,p5,p6,p7,p8).start();
} catch (IOException ex) {
Logger.getLogger(Openprogramtest.class.getName()).log(Level.SEVERE, null, ex);
}

Each String you pass to ProcessBuilder is a separate argument (except the first one, which is the command).
Think of it like the args[] which are passed to your main method. Each String would be a separate element in the array.
I suspect that p1 is been interpreted as a single argument, when it should actually be two...
Try separating this argument into two separate parameters
String location = "C:\\Windows\\System32\\javaw.exe";
String p1="-cp";
String p2="jts.jar;total.2012.jar";
String p3="-Dsun.java2d.noddraw=true";
String p4="-Dswing.boldMetal=false";
String p5="-Dsun.locale.formatasdefault=true";
String p6="-Xmx768M";
String p7="-XX:MaxPermSize=128M";
String p8="jclient/LoginFrame" ;
String p9 = "C:\\Jts";
Amendment
Look at the -cp parameter, it appears that the class path elements are relative to the location that the command is executed. This suggests that you need to use the ProcessBuilder#directory(File) to specify the location that the command should executed from.
For example, if you program is installed in C:\Program Files\MyAwesomeApp, but you run it from the context of C:\Desktop, then Java won't be able to find the Jar files it needs, generally raising a ClassNotFound exception.
Instead, you need to tell ProcessBuilder that you want the command to executed from within the C:\Program Files\MyAwesomeApp context.
For example...
ProcessBuilder pb = new ProcessBuilder(...);
pb.directory(new File("C:\Program Files\MyAwesomeApp"));
// Other settings...
Process p = pb.start();
Updated from running example
Just to make the point. I built myself a little Java program that simple printed a simple message to the standard out.
When I run this, it works as expected...
try {
String params[] = new String[]{
"C:\\Windows\\System32\\javaw.exe",
"-cp",
"C:\\...\\TestSimpleProcessBuilder\\build\\classes",
"-Dsun.java2d.noddraw=true",
"-Dswing.boldMetal=false",
"-Dsun.locale.formatasdefault=true",
"-Xmx768M",
"-XX:MaxPermSize=128M",
"testsimpleprocessbuilder/HelloWorld",
"Boo"
};
ProcessBuilder pb = new ProcessBuilder(params);
pb.redirectErrorStream();
Process p = pb.start();
InputStream is = p.getInputStream();
int in = -1;
while ((in = is.read()) != -1) {
System.out.print((char) in);
}
is = p.getErrorStream();
in = -1;
while ((in = is.read()) != -1) {
System.out.print((char) in);
}
System.out.println("p exited with " + p.exitValue());
} catch (IOException ex) {
Logger.getLogger(TestSimpleProcessBuilder.class.getName()).log(Level.SEVERE, null, ex);
}
When I change the arguments from
"-cp",
"C:\\...\\TestSimpleProcessBuilder\\build\\classes",
to
"-cp C:\\...\\TestSimpleProcessBuilder\\build\\classes",
It fails with...
And outputs
Unrecognized option: -cp
C:\DevWork\personal\java\projects\wip\StackOverflow\TestSimpleProcessBuilder\build\classes
And if you're wondering, this is the little test program I wrote that gets run...
package testsimpleprocessbuilder;
public class HelloWorld {
public static void main(String[] args) {
System.out.println("Hello world - world says " + (args.length > 0 ? args[0] : "Nothing"));
}
}

Runtime.getRuntime.exec() not working for the linux command "tar -xvf filename.tar"

I am trying to untar a file on a Unix machine, using a Java batch application.
Source Code:
String fileName = "x98_dms_12";
Runtime.getRuntime().exec("gunzip "+ fileName + ".tar.gz");
System.out.println(" Gunzip:"+"gunzip "+ fileName + ".tar.gz");
Runtime.getRuntime().exec("tar -xvf "+ fileName + ".tar");
System.out.println(" Extract:tar -xvf "+ fileName + ".tar");
Problem Description:
When I run the batch program it does not (completely) work. Only the gunzip command works, converting my fileName.tar.gz to fileName.tar. But the untar command does not seem to do anything, and there is no error or exception in my log or Unix console.
When I run the same commands in a Unix prompt they work fine.
Notes:
The path of execution is correct because it converts my *.tar.gz to *.tar
I cannot use "tar -zxvf fileName.tar.gz" since the attribute "z" does not work on my system.
There is no error or exception thrown.
Please do help.

A couple of things:
The tar command will expand a file relative to your working directory, which might need to be set for your Java Process objects
You should wait for the unzip process to complete before launching into the untar process
You should process the output streams from the processes.
Here is a working example that you can extend/adapt. It uses a separate class to deal with the process output streams:
class StreamGobbler implements Runnable {
private final Process process;
public StreamGobbler(final Process process) {
super();
this.process = process;
}
#Override
public void run() {
try {
final BufferedReader reader = new BufferedReader(
new InputStreamReader(process.getInputStream()));
String line = null;
while ((line = reader.readLine()) != null) {
System.out.println(line);
}
reader.close();
} catch (final Exception e) {
e.printStackTrace();
}
}
}
public void extractTarball(final File workingDir, final String archiveName)
throws Exception {
final String gzFileName = archiveName + ".tar.gz";
final String tarFileName = archiveName + ".tar";
final ProcessBuilder builder = new ProcessBuilder();
builder.redirectErrorStream(true);
builder.directory(workingDir);
builder.command("gunzip", gzFileName);
final Process unzipProcess = builder.start();
new Thread(new StreamGobbler(unzipProcess)).start();
if (unzipProcess.waitFor() == 0) {
System.out.println("Unzip complete, now untarring");
builder.command("tar", "xvf", tarFileName);
final Process untarProcess = builder.start();
new Thread(new StreamGobbler(untarProcess)).start();
System.out.println("Finished untar process. Exit status "
+ untarProcess.waitFor());
}
}

The code below will print the output of the command executed. Check if it returns any error.
Process p = Runtime.getRuntime().exec("tar -xvf "+ fileName + ".tar");
BufferedReader br = new BufferedReader(new InputStreamReader(p.getInputStream()));
String line = null;
while ((line = br.readLine()) != null) {
System.out.println(line);
}

The problem is the commands which we give is UNIX command so it wont work in windows environment. I had written a script file to overcome this problem thanks all for you help. The Runtime.getRuntime.exec() will take some time to execute the command given so after each exec() give thread.wait(3000) to complete the process and goto next thread.

Better way of opening a Document from Java?

I've been using the following code to open Office Documents, PDF, etc. on my windows machines using Java and it's working fine, except for some reason when a filename has embedded it within it multiple contiguous spaces like "File[SPACE][SPACE]Test.doc".
How can I make this work? I'm not averse to canning the whole piece of code... but I'd rather not replace it with a third party library that calls JNI.
public static void openDocument(String path) throws IOException {
// Make forward slashes backslashes (for windows)
// Double quote any path segments with spaces in them
path = path.replace("/", "\\").replaceAll(
"\\\\([^\\\\\\\\\"]* [^\\\\\\\\\"]*)", "\\\\\\\"$1\"");
String command = "C:\\Windows\\System32\\cmd.exe /c start " + path + "";
Runtime.getRuntime().exec(command);
}
EDIT: When I run it with the errant file windows complains about finding the file. But... when I run the command line directly from the command line it runs just fine.

If you are using Java 6 you can just use the open method of java.awt.Desktop to launch the file using the default application for the current platform.

Not sure if this will help you much... I use java 1.5+'s ProcessBuilder to launch external shell scripts in a java program. Basically I do the following: ( although this may not apply because you don't want to capture the commands output; you actually wanna fire up the document - but, maybe this will spark something that you can use )
List<String> command = new ArrayList<String>();
command.add(someExecutable);
command.add(someArguemnt0);
command.add(someArgument1);
command.add(someArgument2);
ProcessBuilder builder = new ProcessBuilder(command);
try {
final Process process = builder.start();
...
} catch (IOException ioe) {}

The issue may be the "start" command you are using, rather than your file name parsing. For example, this seems to work well on my WinXP machine (using JDK 1.5)
import java.io.IOException;
import java.io.File;
public class test {
public static void openDocument(String path) throws IOException {
path = "\"" + path + "\"";
File f = new File( path );
String command = "C:\\Windows\\System32\\cmd.exe /c " + f.getPath() + "";
Runtime.getRuntime().exec(command);
}
public static void main( String[] argv ) {
test thisApp = new test();
try {
thisApp.openDocument( "c:\\so\\My Doc.doc");
}
catch( IOException e ) {
e.printStackTrace();
}
}
}