I am running a Shell script using cygwin.
Process p;
InputStream in;
BufferedReader br;
String line;
String cmd;
cmd = "D:/cygwin/bin/bash -c '/bin/test/app.sh" +three_ltr_id+""+mon_code+""+year_code+""+part_no+""+version_no+" '";
System.out.println("EXECUTING: " + cmd);
p = Runtime.getRuntime().exec(cmd);
in = p.getInputStream();
p.waitFor();
br = new BufferedReader(new InputStreamReader(in));
System.out.println("OUT:");
while ((line = br.readLine()) != null) {
System.out.println(line);
System.out.println("SCRIPT EXECUTED PROPERLY");
This is showing EXECUTING and the commands that I passed to script.
If I go inside D:/cygwin/bin/test folder and run the same command it works.
When I run the same command at the command line it won't work.
You need to start reading the input from p.getInputStream() immediately, and keep reading it until there is no more. On Windows, there is little or no buffer in the pipe, and the process will hang once it is filled.
Same is true for the error stream. You could launch threads to read both streams, or there's an option in the way you launch processes to combine regular output and errors, and you can just read them from there.
Related
I'm trying to use a shell script in a java file.
The script runs then prints out the content of a file, and asks the user if its ok to continue
I can start the script off with this and see some output:
try {
process = processBuilder.start();
process.getOutputStream();
process.getInputStream();
process.getErrorStream();
BufferedReader reader = new BufferedReader(new InputStreamReader(process.getInputStream()));
String output_line = "";
while ((output_line = reader.readLine()) != null) {
System.out.println(output_line);
}
but I think when the file is closed it drops out of the while loop.
I was hoping to see "OK to proceed?" but it's just getting stuck on the last line of the file.
is there a way to keep reading from the command line until the script ends?
I am running grep command via my Java program. Running grep on the command line sometimes writes an error on stderr of the kind: No such file or directory. I want to detect in my Java program whenever this error happens as a result of executing the grep command via the program. How can I achieve this goal of mine? This is what I've written so far:
Runtime rt = Runtime.getRuntime();
String[] cmd = {"/bin/sh", "-c", "grep -c 'Search_String' /path/to/file(s)/being/searched"};
Process proc = rt.exec(cmd);
BufferedReader is = new BufferedReader(new
InputStreamReader(proc.getInputStream()));
String line;
while ((line = is.readLine()) != null) {
System.out.println(line);
}
You can detect if the process returned with an error; as #Dakoda mentions, exitValue() won't have the exit value until the process ends, but using waitFor() will block until the process ends and returns the exit value:
int rv = rt.waitFor();
if (rv != 0) { ... }
Error output is usually on stderr rather than stdout, so to read errors you'd use:
BufferedReader is = new BufferedReader(
new InputStreamReader(proc.getErrorStream()));
I want to execute a command mspview -r "C:\\Users\\SS\\Desktop\\phantomjs-1.9.2-windows\\image.tif". How can I do it via Java code? I am trying to do this with a batch file. The same command when I run with the help of RUN. I am getting correct output. I have executed a .exe program with the help of a batch file with the following code C:\Users\SS\Desktop\phantomjs-1.9.2-windows\phantomjs.exe.
You're basically asking how to run shell commands in java, right?
Runtime.getRuntime().exec("whatever system call you want");
You need to use ProcessBuilder
Process process = new ProcessBuilder(
"C:\\PathToExe\\exe.exe","param1","param2").start();
InputStream is = process.getInputStream();
InputStreamReader isr = new InputStreamReader(is);
BufferedReader br = new BufferedReader(isr);
String line;
System.out.printf("Output of running %s is:", Arrays.toString(args));
while ((line = br.readLine()) != null) {
System.out.println(line);
}
code that is already found on stackoverflow
Execute external program in java
I used to write PHP code to execute pig command, it worked well,
Now I switch to Java but seems it won't work, here is my code:
String pigCommand = "pig -x local -p ouput=/tmp my_pig_script.pig";
Runtime r = Runtime.getRuntime();
Process p;
int exitVal;
try {
p = r.exec(pigCommand);
exitVal = p.waitFor();
BufferedReader br = new BufferedReader(new InputStreamReader(p.getInputStream()));
String line = null;
while((line = br.readLine()) != null) {
System.out.println(line);
}
br.close();
System.out.println("exitVal: " + exitVal);
System.out.println("Done");
If I run the that pig command in console directly, it works, if I replace
that Pig command with other shell command say 'ping www.yahoo.com', and run the
java Program, it works too. So what might be the problem? thanks
You should use PigServer to execute pig scripts from java programs. It is more foolproof and more portable.
Also see this answer: https://stackoverflow.com/a/11299259/373151
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