Develop Reference

Why does the output of my shell script doesn't print in console?

I am trying to print the output of a shell script on the console using java. When I manually run the script, I get
C:/Users/user1/Desktop/shell.sh: line 78: /usr/ucb/ps: No such file or directory
<STATUS>: Probe [ devicename ] is not running!
But, when I try to run it on my Java program, the output is not being printed on the console.
My code is:
ProcessBuilder processBuilder = new ProcessBuilder("C:/Program Files/Git/git-bash.exe","C:/Users/user1/Desktop/shell.sh");
try {
Process process = processBuilder.start();
StringBuilder output = new StringBuilder();
BufferedReader reader = new BufferedReader(
new InputStreamReader(process.getInputStream()));
String line;
while ((line = reader.readLine()) != null) {
output.append(line + "\n");
System.out.println(line);
}
int exitVal = process.waitFor();
if (exitVal == 0) {
System.out.println("Success!");
System.out.println(output);
System.exit(0);
} else {
//abnormal...
}
} catch (IOException e) {
e.printStackTrace();
} catch (InterruptedException e) {
e.printStackTrace();
}
The only output I am getting is "Success". When I debugged my code, I found that the code never enters the condition
while ((line = reader.readLine()) != null)
even though, in the bash terminal, there are lines of output. Why is this happening?
I am stuck at this point and I couldn't find any other explanations for this problem. Kindly help.

You are running git-bash.exe which opens as a windows application. Although Java has access to the stdout/stderr streams of git-bash.exe, these are not necessarily the same as the stdout/err of the internal launch of your shell script within git-bash.exe.
One way to see the stdout/err of your command would be to make a java friendly version of the .sh script which launches your original sh and redirects output to a specific files which you can then access within java afterwards.
ProcessBuilder pb = new ProcessBuilder("C:/Program Files/Git/GIT-BASH.EXE","/c/Users/blah/somescript.sh");
somescript.sh:
#!/bin/sh
runtheoriginalcommand > ~/somepath.out 2> ~/somepath.err
You could also add extra args to wrapper to pass the out/err files to be used so there is no contention with any other launches or hardcoded output files.

Reopen an already running application(.exe) using java

I have a java program that opens up a .exe file. What i want to do is,
1)Run the .exe file when the java program is executed - Runs perfectly
2) When running the same code again, I want to reopen the previously executed exe.I dont want the .exe file to execute again.
EDIT:
Is there a way to do the above? My only concern is the 2nd question. I have made the 1st question to work

On the request of Luffy. This is the code that i had used to get the list of running process and check whether a particular exe is running or not. Hope it helps for others.
try
{
String line;
String pidInfo = "";
Process proc = Runtime.getRuntime().exec("wmic.exe");
BufferedReader input = new BufferedReader(new InputStreamReader(proc.getInputStream()));
OutputStreamWriter oStream = new OutputStreamWriter(proc.getOutputStream());
oStream .write("process where name='test.exe'");
oStream .flush();
oStream .close();
while ((line = input.readLine()) != null) {
pidInfo+=line;
}
input.close();
if(pidInfo.contains("test.exe"))
{
System.out.println("exe already running");
}
else
{
System.out.println("exe not running");
Process p = Runtime.getRuntime().exec(new String[] {"C:\\Program Files (x86)\\ToTestEXE\\test.exe"});
}
}
catch (IOException e)
{
e.printStackTrace();
}

Access files and folders in Jar files

There are many similar questions to this but this is not a duplicate. This is similar to "Can't access files in Jar file" but there is a slight difference. With a lot of experimentation and forum reading, I managed to access the contents of a file and display them from within the Jar file. The problem is that if I were to put the file inside a folder then my program would no longer work even though it works when I run the class file. This is a problem because when I make games and other programs I like having different folders for organisation like "maps" and "spritesheets". I made an experimental program to route out the problem and here is the code for it:
try {
InputStream is = getClass().getResourceAsStream("folder\\test.txt");
InputStreamReader isr = new InputStreamReader(is);
BufferedReader br = new BufferedReader(isr);
String line;
while ((line = br.readLine()) != null) {
System.out.println(line);
}
br.close();
isr.close();
is.close();
} catch (Exception ex) {}
I didn't do anything in the catch section because I had already used it to find the area with the problem. Here is my directory structure:
JarFileText
classes
com
sayedhajaj
folder
test.txt
JarFileText.class
test.txt
source
com
sayedhajaj
JarFileText.java
When I try to access the copy of the text file that is not in the folder, everything works fine. However, if I try to access the copy in "folder", null is returned.

This is the solution:
try {
InputStream is = getClass().getResourceAsStream("folder/test.txt");
InputStreamReader isr = new InputStreamReader(is);
BufferedReader br = new BufferedReader(isr);
String line;
while ((line = br.readLine()) != null) {
System.out.println(line);
}
br.close();
isr.close();
is.close();
} catch (Exception ex) {}

Print output of c++ .exe file in java

I want to run c++ .exe file from java and also want to print the output of .exe file.i tried and succeed to run c++ .exe file from java ,but i am not getting how can i print the output(in java output field) of c++ .exe file using java,i tried using processExitValue and waitfor methods but not getting desired output.The java code is here
int processExitVal = 0;
try {
Process p = Runtime.getRuntime().exec("cmd /c start rs.exe");
processExitVal = p.waitFor();
// p.getOutputStream();
//InputStreamReader ir=new InputStreamReader(p.getInputStream());
//BufferedReader t = new BufferedReader((new InputStreamReader(p.getInputStream())));
// int y=Integer.parseInt(t.readLine());
InputStream in=p.getInputStream();
System.out.println(in.read());
//System.out.println("output"+Process.getOutputStream());
} catch (IOException e) {
System.out.println("IOException");
e.printStackTrace();
} catch (InterruptedException e) {
System.out.println("InterruptedException");
e.printStackTrace();
}
System.out.println(processExitVal);
System.out.println("Execution complete");
}
I will be thankful if u will help me out this problem. Thanks in advance

You could use a Scanner and then read lines from it. Are you sure your process is writing something on the standard output?
Edit:
read(): Reads the next byte of data from the input stream.
You have to use a Scanner:
Scanner scan = new Scanner(p.getInputStream());
String line = scan.getNextLine();
Regarding Deestan's answer: getInputStream() is the correct method here, we want the output of the process, that's an input for the application.

Use "rs.exe" instead of "cmd /c start rs.exe"
As example:
Process process = Runtime.getRuntime().exec("rs.exe");
BufferedReader in = new BufferedReader(new InputStreamReader(process.getInputStream()));
String line = null;
while((line = in.readLine()) != null) {
System.out.println(line);
}

How to edit file on console from Java?

I'm trying to edit a file from CLI. I'm executing the nano command (I know that command will always be available); when I execute it, I can see nano's output but I cannot interact with it. How can I pass user input to the command? Do you have a better idea to easily edit a file from within my Java app?
This is my code:
String command = "nano /tmp/163377867.txt ";
try {
Process process = Runtime.getRuntime().exec(command);
InputStream inputStream = process.getInputStream();
InputStreamReader inputStreamReader = new InputStreamReader(inputStream);
BufferedReader bufferedReader = new BufferedReader(inputStreamReader);
String line;
while ((line = bufferedReader.readLine()) != null) {
System.out.println(line);
}
} catch (IOException e) {
e.printStackTrace();
}

The problem with Java's Runtime.exec is that it connects stdin and stdout to "pipes," while many console programs need a TTY device.
One way to solve this problem is to make the Java program's controlling terminal available to the program you execute:
Process proc = Runtime.getRuntime().exec(new String[]{
"sh", "-c", command+" </dev/tty >/dev/tty"});
proc.waitFor(); // wait for user to finish editing the file