Execute a unix command

How is a unix command executed in Java? What is the syntax?

Hi,
The best way to use a UNIX command (or another command from another operating system) is to use java.lang.Runtime class ( one of the exec method)
It will return you a Process class which represents your UNIX command being executed.
Once you finish with your process, you just have to destroy it using the destroy method of the Process class.
Hope you get the picture and good luck.
touco
Javaholic & love Duke dollars.

Similar Messages

How to execute a Unix Command in java

Hi, Iam trying to execute a unix command on Sun Solaris by passing that command to a java program. How can I achieve this?
Thanks in advance.

Have a look at the javadoc around the Runtime.exec() method. If the command is a shell command then you might have to execute a shell as well as the command.
For example, if you wanted to run a unix command 'ls -l > output.txt' the you might have to pass the following string into the exec() method,
"/bin/sh ls -l > output.txt'

Permission denied when I execute a unix command from within my java applet.

Hi Gang,
Forgive me if this is not the appropriate forum for this problem. I'm posting this problem on this forum since I got no answers on the other forum I posted on.
I've written a simple java applet that runs a unix command and then displays some information. The applet compiles fine, and runs perfectly from the command line on my unix system.
However, when I point a browser at the applet from my desktop PC I get the following error as taken from the java console:
Exception in thread "AWT-EventQueue-2" java.security.AccessControlException: access denied (java.io.FilePermission <<ALL FILES>> execute)
This is of course the first line in a long line of error messages. It appears that I am not able to execute a command on the unix system through my applet. I know the problem is with trying to execute a unix command since commenting it causes no error in the web browser. This is the command I'm using in java to execute the unix command:
p = Runtime.getRuntime().exec("ps");
Here's the html file on the unix system:
<html>
<head></head>
<body>
<appletcode=G.class height="250" width="400">
Your browser does not support the applet tag.
</applet>
</body>
</html>
I won't list the java code since it is compiling and working on the command line. But, if you want to see it I'll provide it.
I've done quite a bit of research on this and it seems that a great number of people have similar problems reading or executing files through java. I have yet to find a solution to this problem.
Here are some details about my setup:
Server:
HP9000 running HP/UX 11.23
Apache Web Server 2.0.35
Java 1.5
Desktop PC:
Win2K Pro
Internet Explorer 6
Java 1.6
If you have a solution I would be very grateful! This problem is keeping me from writing my application!
thanks!
kev

Multi-posted.
Already answered here http://forum.java.sun.com/thread.jspa?threadID=5225314&messageID=9916327#9916327

Permission denied when I execute a unix command from inside my Java applet.

Hi Gang,
Forgive me if I'm posting this to the wrong forum! I didn't get any answers on the previous forum that I posted this to.
I've written a simple java applet that runs a unix command and then displays some information. The applet compiles fine, and runs perfectly from the command line on my unix system.
However, when I point a browser at the applet from my desktop PC I get the following error as taken from the java console:
Exception in thread "AWT-EventQueue-2" java.security.AccessControlException: access denied (java.io.FilePermission <<ALL FILES>> execute)
This is of course the first line in a long line of error messages. It appears that I am not able to execute a command on the unix system through my applet. I know the problem is with trying to execute a unix command since commenting it causes no error in the web browser. This is the command I'm using in java to execute the unix command:
p = Runtime.getRuntime().exec("ps");
Here's the html file on the unix system:
<html>
<head></head>
<body>
<appletcode=G.class height="250" width="400">
Your browser does not support the applet tag.
</applet>
</body>
</html>
I won't list the java code since it is compiling and working on the command line. But, if you want to see it I'll provide it.
I've done quite a bit of research on this and it seems that a great number of people have similar problems reading or executing files through java. I have yet to find a solution to this problem.
Here are some details about my setup:
Server:
HP9000 running HP/UX 11.23
Apache Web Server 2.0.35
Java 1.5
Desktop PC:
Win2K Pro
Internet Explorer 6
Java 1.6
If you have a solution I would be very grateful! This problem is keeping me from writing my application!
thanks!
kev

Multi-posted.
Already answered here http://forum.java.sun.com/thread.jspa?threadID=5225314&messageID=9916327#9916327

Execute an Unix command with pipe

Hi,
How do I execute a unix command with pipe from JAVA runTime.exec(cmd)? for example: "ls -l |wc -l"
should return number of files. However, there is no output result. If I use "ls -l" as command argument, it gives file list.
Here is my program:
public static void main(String[] args) {
try {
Runtime runCmd = Runtime.getRuntime();
System.out.println("sys testing");
Process retProc = runCmd.exec(args[0]);
BufferedReader bread = new BufferedReader
(new InputStreamReader(retProc.getInputStream()) );
String out = bread.readLine();
while ( out != null ) {
System.out.println(out);
out = bread.readLine();
DataOutputStream outSt = new DataOutputStream(retProc.getOutputStream() );
outSt.writeChars(args[1]);
outSt.flush();
} catch (Exception ie) {
ie.printStackTrace();
Thanks in advance,
Jeff

I got my answer !
No need to reply

Problem in executing a unix command through java

hi
i'm trying to execute unix command through java
simple shell command like "ls -l >test " but i'm not able to see the result.
there are no error messages.
Code is:
import java.lang.Runtime.*;
class ExecDemo
     public static void main(String[] args)
          Runtime r=Runtime.getRuntime();
          Process p=null;
          try
               p=r.exec("ls -l > test");
          catch (Exception e)
               System.out.println("Error executing nedit.");
}can anyone help please.

get the the inputStream of the runtime object after executing the command.
now use the readLine() function until it becomes null.
egs: with reference to ur code.
InputStream is=p.getInputStream()
while(is!=null)
String s=is.readLine();
if the command don't execute try giving the full path also like /sbin/ls -l

Executing multiple UNIX commands

Hello
I would like to execute from a Java application the UNIX command :
ls -l | grep ob
I first execute the command "ls -l" and write the output stream in the input stream of the command "grep ob"
My problem is that the second command is waiting for the EOT character and i don't know how to send it. I tried to write the char 4 but it doesn't work
Any idea to run commands with pipes ?
Chris

I reply to myself in case someone else wants to do that job :
    private static byte[] execUNIXcmd(String commande, byte[] outputData, boolean closeStream) {
     Runtime runtime = Runtime.getRuntime();
     Process process = null;
     InputStream inputStream = null;
     OutputStream outputStream = null;
     byte[] bBuf = null;
     try {
         process = runtime.exec(commande);
         outputStream = process.getOutputStream();
         inputStream = process.getInputStream();
         if (outputData != null) {
          outputStream.write(outputData);
         if (closeStream) {
          outputStream.close();
         inputStream = process.getInputStream();
         process.waitFor();
         bBuf = new byte[inputStream.available()];
         inputStream.read(bBuf, 0, inputStream.available());
         return bBuf;
     } catch (InterruptedException e) {
         System.err.println("ERROR : Enable to wait the process");
         return null;
     } catch (IOException e) {
         System.err.println("ERROR : Enable to read input lines");
         return null;
    // Fonction principale
    public static void main(String s[]) {
     byte[] result = null;
     result = execUNIXcmd("ls -l", null, false);
     result = execUNIXcmd("grep java", result,true);
     result = execUNIXcmd("grep ~", result,true);
     System.out.println(new String(result));
    }I missed to close the outputStream of the command waiting for it.
Chris

Execute Unix command on login

Hello, is it possible to execute a unix command on user login?
I want that every time a user login on a mac at my company, a unix command be executed.
Is this case, this is the command: defaults write com.apple.mail NSPreferredMailCharset "UTF-8"
thks in advance

{quote}Loginwindow Scripts
Another way to run applications at login time is to launch them using a custom shell script. Mac OS X provides two options for launching scripts when the user logs in. When creating your script file, keep the following in mind:
* The permissions for your script file should include execute privileges for the appropriate users.
* Scripts launched by loginwindow are run as root. Therefore, you should thoroughly test your scripts before deploying them to make sure they do not adversely affect the user's system.
*In your script, the variable $1 returns the short name of the user who is logging in.
* Other login actions wait until your hook finishes executing. Therefore, have your script do what it needs to do quickly and then exit. {quote}
I want the script to be run as the current user that does the login, and not as the root. I think that if its run as root, it changes nothing in the user. Does this root issue apllies to the Zerwas method?
It depends on how Zerwas was thinking you'd implement it. If you added it to each user's login items, it should run as the user. If you create a startup item to run it, it will run as root. I'm assuming Zerwas was suggesting the former because there would be no point in wrapping the shell script in an AppleScript if you are going to turn it into a startup item.
What you might be able to do - at least with the loginwindow script - would be to explicitly run the command as the user by making use of the fact that the user name is passed to the loginwindow script as $1. I've never used loginwindow scripts but it seems as though it should work.
Another possibility would be to use a LaunchAgent. These are really intended to manage background processes, though, and it seems an unnecessary use of resources to load one which will only ever be run at startup.
Can I ask why you wish to run the script every time a user logs in? Is the concern that the default will get set to something else and needs to be reset regularly?
- cfr

How to execute unix command in java or jsp

have a peace day,
please send some sample code for
"execute the unix command in java or jsp"
thank you
regards
rex

i execute this coding
its compiling. while running i get the error " java.io.IOException: CreateProcess: \ls-l error=2 "
import java.io.*;
import java.util.*;
public class Test
   public static void main(String[] args) throws Exception
     try
          String[] cmd = {"/ls-l"};
Runtime.getRuntime().exec(cmd);
     catch (Exception e)
           System.out.println(e);
}what can i do for that
thank u

How to execute unix command from ODI Procedure

Hi,
I am trying to execute below unix command from ODI Procedure (Command on Target tab) but I am getting the error "java.io.IOException: Cannot run program "cd": error=2, No such file or directory" but when I try to execute the same command using OdiOSCommand, it is executing successfully. I don't want to use shell script to execute this command. Is there any specific syntax am I missing to execute this command from ODI procedure?
cd /project3/tmt/;ls *.dmp > dmplist.lst
Please help me on this...
Thanks
MT

Hi nahlikh,
Thank you for the reply.
I used below command in Procedure but still getting the same error as "java.io.IOException: Cannot run program "OdiOSCommand": error=2, No such file or directory".
OdiOSCommand "-COMMAND=cd /project3/tmt/;ls *.dmp > dmplist.lst"
as I mentioned earlier if I use the command cd /project3/tmt/;ls *.dmp > dmplist.lst in OdiOSCommand tool it is executing successfully without any issues.
any thoughts appreciated to get a solution for this issue.
Thanks
MT

How to execute a unix/dos command in Java

Hi,
I want to execute dos/unix commands in my java program. Can anyone tell me how to do this. Say I want to restart my httpd daemon using the command: "service httpd restart" or test my httpd.conf file using the command "testparn"
thanks in advance
Hugo Hendriks

hallo,
test this:
Process p = Runtime.getRuntime().exec(Your_Programm);
p.waitFor();
LineNumberReader lnr = new LineNumberReader(new InputStreamReader(p.getInputStream()));
Your_Programm must be a shellscript. regard that your java programm must have the right to start the httpd!
Carsten Bluetner

Execute unix command using java

Hello
Can we execute a unix command using java? If it is how we can execute. Is this affect the performance of the program.
Thanks

I tried what you said. But its not working and returning error message,
java.io.IOException: CreateProcess: ls -a error=2
     at java.lang.ProcessImpl.create(Native Method)
     at java.lang.ProcessImpl.<init>(Unknown Source)
     at java.lang.ProcessImpl.start(Unknown Source)
     at java.lang.ProcessBuilder.start(Unknown Source)
     at java.lang.Runtime.exec(Unknown Source)
     at java.lang.Runtime.exec(Unknown Source)
     at java.lang.Runtime.exec(Unknown Source)
If i try this statement,
Runtime.getRuntime().exec("c\windows\notepad");
It is working fine.
Any idea about this.
Plz ...........

Execute unix commands from Java

Hi,
I have a client application running on windows. This client should connect to a unix server and check for the existence of a file and display the result as "File found/File not found". In order to connect from windows to the unix server, I used the sockets and the connection is successfully established. The second part is to check for the presence of the file in unix server. I searched in google.com and the option I found to execute a unix command from java is the "Runtime.exec()". Runtime.exec is considered as the less effective (not a favorable) one.
Is there any other option available (other than the Runtime) to execute the unix command from java? Can you please let me know.
Thanks a lot
Aishu

So, please let me know how I can execute the above unix commands without Runtime.exec()You have a client and a server.
You want something to run on the server, not the client.
That means that something must in fact being running on the server before the client does anything at all.
For example telnet. Or a J2EE server application.
So is something like that running?
If not then there absolutely no way to do what you want, even with Runtime.exec().
If yes then what you do depends on what is running. So Runtime.exec() would be pointless if a J2EE server was running.

How execute UNIX commands?

Hi, does anyone know how to execute an UNIX command in Java? Command->
find -name '*.dmp' in a directory called /db/Backup? What are the parameters that i've to pass in for this function-> Runtime.getRuntime().exec(); ??? And how do i get the filenames of the files searched?

Do i have to pass the path to-> Runtime.getRuntime().exec();Of course. Just do the following:
final String command = ;
Runtime.getRuntime().exec("find /tmp -name Bar.class");Or, you can use the alternative exec and pass your command-line arguments in a String array.
Check the AP:
http://java.sun.com/j2se/1.4.1/docs/api/java/lang/Runtime.html#exec(java.lang.String[])

How does one execute unix commands from within an applet?

Greetings Folks,
I've written a simple java applet that runs a unix command and then displays some information. The applet compiles fine, and runs perfectly from the command line on my unix system.
However, when I point a browser at the applet from my desktop PC I get the following error as taken from the java console:
Exception in thread "AWT-EventQueue-2" java.security.AccessControlException: access denied (java.io.FilePermission <<ALL FILES>> execute)
This is of course the first line in a long line of error messages. It appears that I am not able to execute a command on the unix system through my applet. I know the problem is with trying to execute a unix command since commenting it causes no error in the web browser. This is the command I'm using in java to execute the unix command:
p = Runtime.getRuntime().exec("ps");
Here's the html file on the unix system:
<html>
<head></head>
<body>
<appletcode=G.class height="250" width="400">
Your browser does not support the applet tag.
</applet>
</body>
</html>
I won't list the java code since it is compiling and working on the command line. But, if you want to see it I'll provide it.
I've done quite a bit of research on this and it seems that a great number of people have similar problems reading or executing files through java. I have yet to find a solution to this problem.
Here are some details about my setup:
Server:
HP9000 running HP/UX 11.23
Apache Web Server 2.0.35
Java 1.5
Desktop PC:
Win2K Pro
Internet Explorer 6
Java 1.6
If you have a solution I would be very grateful! This problem is keeping me from writing my application!
thanks!
kev

Multi-posted.
Already answered here http://forum.java.sun.com/thread.jspa?threadID=5225314&messageID=9916327#9916327
Please don't multipost again!

Execute a unix command

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