I found several code snippets for running cmd commands through a Java class, but I wasn't able to understand it.
This is code for opening the cmd
public void excCommand(String new_dir){
Runtime rt = Runtime.getRuntime();
try {
rt.exec(new String[]{"cmd.exe","/c","start"});
} catch (IOException e) {
// TODO Auto-generated catch block
e.printStackTrace();
}
}
And I found some other links for adding other commands such as cd
http://www.coderanch.com/t/109753/Linux-UNIX/exec-command-cd-command-java
How to open the command prompt and insert commands using Java?
Can anyone help me to understand how to cd a directory such as:
cd C:\Program Files\Flowella
then run other commands on that directory?
One way to run a process from a different directory to the working directory of your Java program is to change directory and then run the process in the same command line. You can do this by getting cmd.exe to run a command line such as cd some_directory && some_program.
The following example changes to a different directory and runs dir from there. Admittedly, I could just dir that directory without needing to cd to it, but this is only an example:
import java.io.*;
public class CmdTest {
public static void main(String[] args) throws Exception {
ProcessBuilder builder = new ProcessBuilder(
"cmd.exe", "/c", "cd \"C:\\Program Files\\Microsoft SQL Server\" && dir");
builder.redirectErrorStream(true);
Process p = builder.start();
BufferedReader r = new BufferedReader(new InputStreamReader(p.getInputStream()));
String line;
while (true) {
line = r.readLine();
if (line == null) { break; }
System.out.println(line);
}
}
}
Note also that I'm using a ProcessBuilder to run the command. Amongst other things, this allows me to redirect the process's standard error into its standard output, by calling redirectErrorStream(true). Doing so gives me only one stream to read from.
This gives me the following output on my machine:
C:\Users\Luke\StackOverflow>java CmdTest
Volume in drive C is Windows7
Volume Serial Number is D8F0-C934
Directory of C:\Program Files\Microsoft SQL Server
29/07/2011 11:03 <DIR> .
29/07/2011 11:03 <DIR> ..
21/01/2011 20:37 <DIR> 100
21/01/2011 20:35 <DIR> 80
21/01/2011 20:35 <DIR> 90
21/01/2011 20:39 <DIR> MSSQL10_50.SQLEXPRESS
0 File(s) 0 bytes
6 Dir(s) 209,496,424,448 bytes free
You can try this:-
Process p = Runtime.getRuntime().exec(command);
If you want to perform actions like cd, then use:
String[] command = {command_to_be_executed, arg1, arg2};
ProcessBuilder builder = new ProcessBuilder(command);
builder = builder.directory(new File("directory_location"));
Example:
String[] command = {"ls", "-al"};
ProcessBuilder builder = new ProcessBuilder(command);
builder = builder.directory(new File("/ngs/app/abc"));
Process p = builder.start();
It is important that you split the command and all arguments in separate strings of the string array (otherwise they will not be provided correctly by the ProcessBuilder API).
Here is a more complete implementation of command line execution.
Usage
executeCommand("ls");
Output:
12/27/2017 11:18:11:732: ls
12/27/2017 11:18:11:820: build.gradle
12/27/2017 11:18:11:820: gradle
12/27/2017 11:18:11:820: gradlew
12/27/2017 11:18:11:820: gradlew.bat
12/27/2017 11:18:11:820: out
12/27/2017 11:18:11:820: settings.gradle
12/27/2017 11:18:11:820: src
Code
private void executeCommand(String command) {
try {
log(command);
Process process = Runtime.getRuntime().exec(command);
logOutput(process.getInputStream(), "");
logOutput(process.getErrorStream(), "Error: ");
process.waitFor();
} catch (IOException | InterruptedException e) {
e.printStackTrace();
}
}
private void logOutput(InputStream inputStream, String prefix) {
new Thread(() -> {
Scanner scanner = new Scanner(inputStream, "UTF-8");
while (scanner.hasNextLine()) {
synchronized (this) {
log(prefix + scanner.nextLine());
}
}
scanner.close();
}).start();
}
private static SimpleDateFormat format = new SimpleDateFormat("MM/dd/yyyy hh:mm:ss:SSS");
private synchronized void log(String message) {
System.out.println(format.format(new Date()) + ": " + message);
}
My example (from real project)
folder — File.
zipFile, filesString — String;
final String command = "/bin/tar -xvf " + zipFile + " " + filesString;
logger.info("Start unzipping: {} into the folder {}", command, folder.getPath());
final Runtime r = Runtime.getRuntime();
final Process p = r.exec(command, null, folder);
final int returnCode = p.waitFor();
if (logger.isWarnEnabled()) {
final BufferedReader is = new BufferedReader(new InputStreamReader(p.getInputStream()));
String line;
while ((line = is.readLine()) != null) {
logger.warn(line);
}
final BufferedReader is2 = new BufferedReader(new InputStreamReader(p.getErrorStream()));
while ((line = is2.readLine()) != null) {
logger.warn(line);
}
}
The easiest way would be to use Runtime.getRuntime.exec().
For example, to get a registry value for the default browser on Windows:
String command = "REG QUERY HKEY_CLASSES_ROOT\\http\\shell\\open\\command";
try
{
Process process = Runtime.getRuntime().exec(command);
} catch (IOException e)
{
e.printStackTrace();
}
Then use a Scanner to get the output of the command, if necessary.
Scanner kb = new Scanner(process.getInputStream());
Note: the \ is an escape character in a String, and must be escaped to work properly (hence the \\).
However, there is no executable called cd, because it can't be implemented in a separate process.
The one case where the current working directory matters is executing an external process (using ProcessBuilder or Runtime.exec()). In those cases you can specify the working directory to use for the newly started process explicitly.
Easiest way for your command:
System.setProperty("user.dir", "C:\\Program Files\\Flowella");
Try this:
Process runtime = Runtime.getRuntime().exec("cmd /c start notepad++.exe");
Once you get the reference to Process, you can call getOutpuStream on it to get the standard input of the cmd prompt. Then you can send any command over the stream using write method as with any other stream.
Note that it is process.getOutputStream() which is connected to the stdin on the spawned process. Similarly, to get the output of any command, you will need to call getInputStream and then read over this as any other input stream.
Stopping and Disabling a service can be done via below code:
static void sdService() {
String[] cmd = {"cmd.exe", "/c", "net", "stop", "MSSQLSERVER"};
try {
Process process = new ProcessBuilder(cmd).start();
process.waitFor();
String line = null;
BufferedReader bufferedReader = new BufferedReader(new InputStreamReader(process.getInputStream()));
while((line = bufferedReader.readLine()) != null) {
System.out.println(line);
}
line = null;
bufferedReader = null;
Process p = Runtime.getRuntime().exec("sc config MSSQLSERVER start= disabled");
p.waitFor();
bufferedReader = new BufferedReader(new InputStreamReader(p.getInputStream()));
while((line = bufferedReader.readLine()) != null) {
System.out.println(line);
}
} catch (Exception e) {
e.printStackTrace();
}
}
Enabling and Starting a service can be done via below code
static void esService() {
String[] cmd = {"cmd.exe", "/c", "net", "start", "MSSQLSERVER"};
try {
Process p = Runtime.getRuntime().exec("sc config MSSQLSERVER start= auto");
//Process p = Runtime.getRuntime().exec("sc config MSSQLSERVER start= demand");
p.waitFor();
String line = null;
BufferedReader bufferedReader = new BufferedReader(new InputStreamReader(p.getInputStream()));
while((line = bufferedReader.readLine()) != null) {
System.out.println(line);
}
line = null;
bufferedReader = null;
Process process = new ProcessBuilder(cmd).start();
process.waitFor();
bufferedReader = new BufferedReader(new InputStreamReader(process.getInputStream()));
while((line = bufferedReader.readLine()) != null) {
System.out.println(line);
}
} catch (Exception e) {
e.printStackTrace();
}
}
Executing command from any folder can be done via below code.
static void runFromSpecificFolder() {
try {
ProcessBuilder processBuilder = new ProcessBuilder("cmd.exe", "/c", "cd \"C:\\Users\\himan\\Desktop\\Java_Test_Deployment\\jarfiles\" && dir");
//processBuilder.directory(new File("C://Users//himan//Desktop//Java_Test_Deployment//jarfiles"));
processBuilder.redirectErrorStream(true);
Process p = processBuilder.start();
p.waitFor();
String line = null;
BufferedReader bufferedReader = new BufferedReader(new InputStreamReader(p.getInputStream()));
while((line = bufferedReader.readLine()) != null) {
System.out.println(line);
}
} catch (Exception e) {
e.printStackTrace();
}
}
public static void main(String args[]) {
sdService();
runFromSpecificFolder();
esService();
}
You can't run cd this way, because cd isn't a real program; it's a built-in part of the command-line, and all it does is change the command-line's environment. It doesn't make sense to run it in a subprocess, because then you're changing that subprocess's environment — but that subprocess closes immediately, discarding its environment.
To set the current working directory in your actual Java program, you should write:
System.setProperty("user.dir", "C:\\Program Files\\Flowella");
public class Demo {
public static void main(String args[]) throws IOException {
Process process = Runtime.getRuntime().exec("/Users/******/Library/Android/sdk/platform-tools/adb" + " shell dumpsys battery ");
BufferedReader in = new BufferedReader(new InputStreamReader(process.getInputStream()));
String line = null;
while (true) {
line = in.readLine();
if (line == null) { break; }
System.out.println(line);
}
}
}
The simplest and shortest way is to use CmdTool library.
new Cmd()
.configuring(new WorkDir("C:/Program Files/Flowella"))
.command("cmd.exe", "/c", "start")
.execute();
You can find more examples here.
one of the way to execute cmd from java !
public void executeCmd() {
String anyCommand="your command";
try {
Process process = Runtime.getRuntime().exec("cmd /c start cmd.exe /K " + anyCommand);
} catch (IOException e) {
e.printStackTrace();
}
}
Here the value adder is use of ampersands to batch commands and correct format for change drive with cd.
public class CmdCommander {
public static void main(String[] args) throws Exception {
//easyway to start native windows command prompt from Intellij
/*
Rules are:
1.baseStart must be dual start
2.first command must not have &.
3.subsequent commands must be prepended with &
4.drive change needs extra &
5.use quotes at start and end of command batch
*/
String startQuote = "\"";
String endQuote = "\"";
//String baseStart_not_taking_commands = " cmd /K start ";
String baseStart = " cmd /K start cmd /K ";//dual start is must
String first_command_chcp = " chcp 1251 ";
String dirList = " &dir ";//& in front of commands after first command means enter
//change drive....to yours
String changeDir = " &cd &I: ";//extra & makes changing drive happen
String javaLaunch = " &java ";//just another command
String javaClass = " Encodes ";//parameter for java needs no &
String javaCommand = javaLaunch + javaClass;
//build batch command
String totalCommand =
baseStart +
startQuote +
first_command_chcp +
//javaCommand +
changeDir +
dirList +
endQuote;
System.out.println(totalCommand);//prints into Intellij terminal
runCmd(totalCommand);
//Thread t = Thread.currentThread();
//t.sleep(3000);
System.out.println("loppu hep");//prints into Intellij terminal
}
public static void runCmd(String command) throws Exception {
Runtime rt = Runtime.getRuntime();
Process proc = rt.exec(command);
}
}
I'm launching from my jar 3 programs with their own parameters.
First and second programs do their job, but not the second one.
Here the code
Runtime rt = Runtime.getRuntime();
String cmdGet= "something";
try {
infolog("Executing command: " + cmdGet);
rt.exec(cmdGet);
}
catch(Exception ex){
infolog("Unable to launch program 2");
saveLog();
}
Here the command for something
D:\Root\Module\Translators\L2Fo\SE_Draft_Update.exe -se_file="F:\Disp\Stage\DC\Ude34ea24x591ecb1c412x\M8486.dft" -input_file="F:\Disp\Stage\DC\Ude34ea24x591ecb1c412x\result\AttributeFile_M8486.txt" -log_file="F:\Disp\Stage\DC\Ude34ea24x591ecb1c412x\result\SELogg_M8486.txt"
In the log I find the proper command launched, but I see that its jobs are not done. So by copying the string manually in the cmd prompt it works
The third program after this one works too.
I do not understand why.
Sometimes a command needs its own cmd-shell.
Then you had to add a "CMD.EXE /C " prefix. This is the reason why
the 'something' line works fine in the cmd-Window.
if (b_shell == true) cmd = "CMD.EXE /C " + cmdstr;
else cmd = cmdstr;
...
rt.exec(cmd);
I pass the b_shell as argument to a wrapper method:
public static void systemCall(String cmdstr,boolean b_shell,Path logfile) throws IOException
Sorry for that answer, perhaps you like to try a version which
is able to wait for the terminating command and returns the output of the command as an ArrayList.
/**
* Executes command 'cmdstr'. The output of the command is stored in a ArrayList-String array
* #param cmdstr The command line to be executed not containing a redirect to an outputfile ( > x.txt )
* #param b_wait If true the command waits until it is finished and 'errmsg' contains the exit value
* #param b_shell If true the command will be started in a shell (uses prefix CMD.EXE /C)
* #param errmsg OUT: Error message
* #return ArrayList-String output or null on error, see errmsg
* #since Last change: 2014.04.30
*/
public static ArrayList<String> systemCallOutputArray(String cmdstr,boolean b_wait,boolean b_shell,/*IO*/StringBuffer errmsg)
{
final String fn="systemCallOutputArray()";
errmsg.setLength(0);
if (cmdstr == null || cmdstr.isEmpty()) { errmsg.append(fn + ": Invalid arg. 'cmdstr' (null or empty)"); return null; }
ArrayList<String> output = new ArrayList<String>();
String cmd ="";
try
{
int exit_value = -1;
Runtime r = Runtime.getRuntime();
Process p = r.exec(cmd);
String line="";
if (b_wait == true)
{
p.waitFor(); // waits until prozess is terminated, throws InterruptedException if wait is interrupted
exit_value = p.exitValue();
BufferedReader input = new BufferedReader(new InputStreamReader(p.getInputStream()));
while ((line = input.readLine()) != null)
{ if (line.isEmpty() == false) output.add(line);
}
input.close();
return output;
}
// the following lines are for b_wait = false
BufferedReader input = new BufferedReader(new InputStreamReader(p.getInputStream()));
while ((line = input.readLine()) != null)
{ if (line.isEmpty() == false) output.add(line);
}
input.close();
return output;
}
catch (Exception e)
{
errmsg.append(fn + " failed: " + e.toString() + " cmd: '" + cmd + "'");
return null;
}
} //---------------- end of systemCallOutputArray()
I am executing grep command from java on a linux file. Its always returning null for the following code.
Process p;
String matchStr="testmatch";
String output = null;
try {
String command = "grep \""+matchStr+"\" "+ filename;
System.out.println("Running command: " + command);
p = Runtime.getRuntime().exec(command);
System.out.println("***********************************");
System.out.println("***********************************");
System.out.println("***********************************");
p.waitFor();
BufferedReader br = new BufferedReader(new InputStreamReader(p.getInputStream()));
while (br.readLine() != null) {
System.out.println("in while loop");
System.out.println("in while loop");
System.out.println("in while loop");
System.out.println(output);
System.out.println("***********************************");
System.out.println("***********************************");
System.out.println("***********************************");
System.out.println("***********************************");
// Process your output here
}
System.out.println("exit: " + p.exitValue());
p.destroy();
} catch (Exception e) {
e.printStackTrace();
}
If i grep it directly it shows output but from java it never gets into while loop.
Please suggest whats wrong here.
The problem is that you do not write anything to output so it stays null. I guess you have to rewrite your while loop like this
while ((output = br.readLine()) != null) {
// Process your output here
}
Take a note that this syntax is discouraged by most style check due to it's abmiguity
Also it's a good idea to place p.waitFor() after while loop so grep would not hang on flushig std(err|out).
UPDATE
Also it is a good idea to use ProcessBuilder (available since java-7) instead of Runtime.getRuntime().exec(...) because you will have more control over the process i.e
final ProcessBuilder builder = new ProcessBuilder();
builder.command("grep", matchStr, filename);
// redirect stderr to stdout
builder.redirectErrorStream(true);
final Process process = builder.start();
BufferedReader br = new BufferedReader(
new InputStreamReader(process.getInputStream()));
String output = null;
while ((output = br.readLine()) != null) {
System.out.println(output);
// Process your output here
}
process.waitFor();
After turning your code into a https://stackoverflow.com/help/mcve it works for me.
Here the file does not exist:
robert#habanero:~$ rm /home/robert/greptest.txt
robert#habanero:~$ javac GrepTest.java && java GrepTest
Running command: grep test /home/robert/greptest.txt
exit: 2
Now the file does exist but does not contain the text to be found:
robert#habanero:~$ echo not found > /home/robert/greptest.txt
robert#habanero:~$ javac GrepTest.java && java GrepTest
Running command: grep test /home/robert/greptest.txt
exit: 1
Now the file exists and contains the text:
robert#habanero:~$ echo test this > /home/robert/greptest.txt
robert#habanero:~$ javac GrepTest.java && java GrepTest
Running command: grep test /home/robert/greptest.txt
test this
exit: 0
Here is the code:
import java.io.*;
public class GrepTest {
public static void main(String[] args) throws Exception {
String command = "grep test /home/robert/greptest.txt";
System.out.println("Running command: " + command);
Process p = Runtime.getRuntime().exec(command);
p.waitFor();
BufferedReader br = new BufferedReader(new InputStreamReader(p.getInputStream()));
String output;
while ((output = br.readLine()) != null) {
System.out.println(output);
}
System.out.println("exit: " + p.exitValue());
p.destroy();
}
}
I was recently struggling with a similar issue, and I believe I the solution I found is an answer also to your problem (though your question is a bit malformed as others have pointed out).
The issue pertrains to the quote marks around your search string,
\""+matchStr+"\"
The java exec command will literally deliver these to the grep command, and instead of searching for matchStr, grep will be looking for "matchStr", and the results will not be what you are expecting.
This applies also in case one is executing the command as an array like
final Process process = Runtime.getRuntime().exec(new String[] { "grep", "-C1000", searchString, fileName } );
Pass the plain searchString without including quotation marks into the string.
I am trying to exceute batch file from a Java program.
The batch file has a command which connects to IBM RTC then gets some data which takes around 30 seconds.
But the program is exiting just after the command is run without waiting for the output.
public static void main(String[] args) {
final String scmCommand = "cmd /c D:\\Coverage\\SCMHistory.bat";
try {
Process process = Runtime.getRuntime().exec(scmCommand);
/*
* final InputStream in = process.getInputStream(); int ch;
* while((ch = in.read()) != -1) { System.out.print((char)ch); }
* final int returnCode = process.waitFor();
*/
try (final BufferedReader b = new BufferedReader(
new InputStreamReader(process.getInputStream()))) {
String line;
while ((line = b.readLine()) != null) {
System.out.println(line);
}
}
**System.out.println("waiting for the process");
process.waitFor();
System.out.println("waiting done");**
} catch (IOException e) {
e.printStackTrace();
} catch (InterruptedException e) {
// TODO Auto-generated catch block
e.printStackTrace();
}
I have tried adding process.waitFor(); but it didnt work.
set scm_path=D:\Coverage\RTC\jazz\scmtools\eclipse
set userId=ADMIN
set pwd=ADMIN
set repWorkspace="1081"
%scm_path%\scm show history -r https://rtc.repo.com:9443/jazz/ -u %userId% -P %pwd% -w "1411.201411" --component core_as D:\Work\201411\make\main_metadata.xml
Out put of which is
Change sets:
(3129) ----$ Sumit, HARI"main metadata is updated to deploy ch..." 03-Mar-2015 04:09 PM
(3130) ----$Sumit, HARI" "Fixed PartyID issue, checked in " 03-Mar-2015 01:01 PM
(3131) ----$ Sumit, HARI" "adding project to main_metada xml file" 26-Feb-2015 02:46 PM
Use start with the /w or start /wait option to run your program in the batch file.
Example
Start "" /w program options ...
Source Start a program, command or batch script (opens in a new window.)
Syntax
START "title" [/D path] [options] "command" [parameters]
Options:
/W or /WAIT Start application and wait for it to terminate.
(for an internal cmd command or a batch file this runs CMD /K)
your batch file is starting a new console window and terminating, even if you use start instead of cmd.
also the /c definition,
/c Carries out the command specified by string and then terminates
try this instead,
final String scmCommand = "D:\\Coverage\\SCMHistory.bat";
if this does not work try this,
final String scmCommand = "D:\Coverage\RTC\jazz\scmtools\eclipse\scm";
String[] envp = new String[5];
envp[0] = "-r https://rtc.repo.com:9443/jazz/";
envp[1] = "-u ADMIN";
envp[2] = "-P ADMIN";
envp[3] = "-w \"1411.201411\" ";
envp[4] = "--component core_as D:\Work\201411\make\main_metadata.xml";
Process process = Runtime.getRuntime().exec(scmCommand, envp);
Code that runs 4 'Street' processes:
for (int i=0; i < NUM_STREETS; i++) {
Process process = runtime.exec("java -classpath \\bin trafficcircle.Street 1 2");
InputStream is = process.getInputStream();
InputStreamReader isr = new InputStreamReader(is);
BufferedReader br = new BufferedReader(isr);
String line;
while ((line = br.readLine()) != null && !line.isEmpty()) {
System.out.println(line);
System.out.flush();
}
InputStream es = process.getErrorStream();
InputStreamReader esr = new InputStreamReader(es);
BufferedReader br2 = new BufferedReader(esr);
while ((line = br2.readLine()) != null && !line.isEmpty()) {
System.out.println(line);
System.out.flush();
}
int exitVal = process.waitFor();
System.out.println("Process exitValue: " + exitVal);
}
Where 'Street' is:
public class Street {
/**
* #param args
* 0 - Simulation run time
* 1 - Flow time interval
*/
public static void main(String[] args) {
System.out.println(args[0]);
System.out.println(args[1]);
System.out.flush();
}
}
Prints out:
Error: Could not find or load main class trafficcircle.Street
Process exitValue: 1
Error: Could not find or load main class trafficcircle.Street
Process exitValue: 1
Error: Could not find or load main class trafficcircle.Street
Process exitValue: 1
Error: Could not find or load main class trafficcircle.Street
Process exitValue: 1
'Street.class' in my Eclipse project is under \bin in package trafficcircle. I thought Runtime.exec would complain first if it wasn't found...what's up with this?
I assume you are getting an error which you are discarding. Try using ProcessBuilder.redirectErrorStream(true);
When you try to run a command it is not run in a shell, and may be getting an error which you don't see on the command line. I would explicitly use
"java","-classpath","bin","trafficcircle.Street","1","2"`
and make sure you are getting any error messages.
another option is to use a shell like
"/bin/bash", "-c", "java -classpath bin trafficcircle.Street 1 2"
Use ./bin (with a dot) to use relative paths.