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How to execute vimdiff command from inside a java program

I have a list of files for which I have to run the vimdiff command and save the output as a html file.I am doing this with Java. Below is the command I am trying to execute
String cmd = "vimdiff -c 'set foldlevel=9999' src/test/resources/testdata/output/html_output_before_changes/file1.html src/test/resources/testdata/output/html_output_after_changes/file2.html -c TOhtml -c 'w! different.html' -c 'qa!'"
When I run the below code, the code is getting executed. But I am not able to see the file getting generated.
Runtime rt = Runtime.getRuntime();
Process process = rt.exec(cmd);
The command is running fine when executed from a terminal. But its not working when executed inside a java program. Can someone help me with this issue? I did a lot of search but not able to proceed with this.

You're using :TOhtml and write the result as different.html. If you're not sure where to locate the file, check the current working directory of the Java process, do a file search of your hard disk, or specify an absolute path in the Vim command to be sure.
You won't see anything from Vim's operation itself. Using process.getInputStream(), you could obtain what Vim wrote to the terminal during its operation, but that would just amount to a garble of characters, as Vim is using special ANSI escape sequences to control the terminal, position the cursor, etc.
To use Vim non-interactively, it is recommended to pass the following options:
-T dumb Avoids errors in case the terminal detection goes wrong.
-n No swapfile.
-i NONE Ignore the |viminfo| file (to avoid disturbing the
user's settings).
-c 'set nomore' Suppress the more-prompt when the screen is filled
with messages or output to avoid blocking.
Without a possibility to interact with Vim (from inside your Java program), a troubleshooting tip is enabling verbose logging: You can capture a full log of a Vim session with -V20vimlog. After quitting Vim, examine the vimlog log file for errors.

After Two days I found the below Solution:
I added the vimdiff command to a shell script and executed it using the following method and it worked like a gem.
Java method
try {
File[] uiDiffDir = getFiles();
for (File file : uiDiffDir) {
String[] cmd = {"sh", shellScriptPath, file1, file2,
outputfile};
Process p = Runtime.getRuntime().exec(cmd);
p.waitFor();
BufferedReader reader = new BufferedReader(new InputStreamReader(
p.getInputStream()));
String line;
while ((line = reader.readLine()) != null) {
System.out.println(line);
}
}
} catch (IOException e) {
e.printStackTrace();
} catch (InterruptedException e) {
e.printStackTrace();
}
shell.sh
vimdiff -c 'set foldlevel=9999' $1 $2 -c TOhtml -c 'w! '"$3"'' -c 'qa!'
Note:
file1 will be passed as a argument in the place of $1
file2 will be passed as a argument in the place of $2
outputfile will be passed as a argument in the place of $3

Running Unix Command in Java

I am running the following code, and it stops at waitfor() function. What could be the reason and how can I solve it?
String line;
Process albumProcess;
try {
albumProcess = Runtime.getRuntime().exec(
"iconv -f UTF-16 -t UTF-8 /home/gozenem/"+ xmlFileName +
".xml | grep albumID");
albumProcess.waitFor();
BufferedReader in = new BufferedReader(
new InputStreamReader(albumProcess.getInputStream()));
ArrayList<String> lineList = new ArrayList<String>();
while ((line = in.readLine()) != null) {
lineList.add(line);
}
result[0] = lineList.size();
albumProcess.destroy();
} catch (Exception e) {}

The | grep ... is not consuming the output from the command as you expect because getRuntime().exec does not understand piping symbols. The process gets bogged down waiting for something to consume its output and its getting passed bogus command line arguments "|", "grep", and "albumId".
A shell will understand | but execv will not, so you need to use bash -c instead to get a shell to do the piping (see java shell for executing/coordinating processes? do the piping yourself (see Pipe between java processes on command shell not reliable working). Java 7 has a new ProcessBuilder class that makes it easy to set up pipes so you can use those if you're only running on a bleeding edge JVM.
Once you've got grep running, if there's a bunch of lines that match, it may still fill up the buffer, so you need something sitting on the buffer consuming the process's output stream. Moving
albumProcess.waitFor();
after the while loop should do it.

I think you should try to read the output from the process before waiting on it. Otherwise, if the command outputs to much then the buffer may get filled.
Have a look at this article which explains how to read from the process: http://www.javaworld.com/javaworld/jw-12-2000/jw-1229-traps.html?page=4

simple console Application using java

Im developing a simple console Application using java. The code is given below
` try {
File file = new File("writer.txt");
writer = new BufferedWriter(new FileWriter(file));
Process myProcess = Runtime.getRuntime().exec("jps -l");
BufferedReader stdout = new BufferedReader(new InputStreamReader(
myProcess.getInputStream()));
String line = stdout.readLine();
while (line != null) {
if (line.contains(".jar")) {
writer.write(line);
System.out.println(line);
}
line = stdout.readLine();
}
writer.close();
}
`
The code will display the currently running the jar in my windows. The output format is displayed 2356 Timeout.jar I want to display it only Timeout.jar How to remove that integer values. Thanks in advance.

Assuming you have "2356 Timeout.jar" in line, this will return just the jar name:
line.substring(line.indexOf(" ") + 1);
I think there must be an easier way to get the running jar though. I did a quick search and you may want to look at these questions:
How to get the path of a running JAR file?
http://arstechnica.com/civis/viewtopic.php?f=20&t=261563

You could:
Apply a regular expression to line before writing it out. (Think start-of-line, then integers, ending at the first whitespace)
Use ls (or dir) as your exec process instead of jps
Just grab the directory listing directly instead of via the external process as per below:
File dir = new File("directoryName");
String[] children = dir.list();
Doing what you have via JPS is probably not a good idea if this isn't a quick one-off app or a learning exercise because of the following note from the jps man page:
NOTE- You are advised not to write scripts to parse jps output since
the format may change in future releases. If you choose to write
scripts that parse jps output, expect to modify them for future
releases of this tool.

Tokenizing the result is one way.
if you are in unix, use awk to get the second field.

If you are using a Linux based OS,
Instead of
Process myProcess = Runtime.getRuntime().exec("jps -l");
try this one
Process myProcess = Runtime.getRuntime().exec("jps -l | cut -d \" \" -f2");

Execute external program from Java

I am trying to execute a program from the Java code. Here is my code:
public static void main(String argv[]) {
try {
String line;
Process p = Runtime.getRuntime().exec(new String[]{
"/bin/bash", "-c", "executable -o filename.txt"});
BufferedReader input = new BufferedReader(
new InputStreamReader(p.getInputStream()));
while ((line = input.readLine()) != null) {
System.out.println(line);
}
input.close();
} catch (Exception err) {
err.printStackTrace();
}
}
My OS is Mac OS X 10.6.
Now, the executable I am trying to run is supposed to spit the output to filename.txt. If I take this command and run it on the terminal, it works fine and the filename.txt gets populated also. But, from my java program the file is not created.
if instead I use executable > filename.txt then the filename.txt is created but is empty. Not sure what's wrong here. The executable I am trying to run is Xtide (if that helps).
I would really appreciate any help I can get.
Thanks,

You cannot redirect output to file and read the output in java. It's one or the other. What you want is this:
Process p = Runtime.getRuntime().exec(new String[]{
"/bin/bash", "-c", "executable -o filename.txt"});
p.waitFor();
BufferedReader input = new BufferedReader(
new InputStreamReader(new FileInputStream("filename.txt")));
while ((line = input.readLine()) != null) {
System.out.println(line);
}
The main changes are:
p.waitFor(), since process execution is asynchronous, so you have to wait for it to complete.
The data is read from the file rather than from the output of the process (since this will be empty.)

The answer from mdma works (and I voted it up), but you might also want to consider the version where you do read the output stream directly from executable:
Process p = Runtime.getRuntime().exec(new String[]{
"/bin/bash", "-c", "executable"});
p.waitFor();
BufferedReader input = new BufferedReader(new InputStreamReader(p.getInputStream())_;
while ((line = input.readLine()) != null) {
System.out.println(line);
}

Correct me if I am wrong, but the symptoms are as follows:
exec("/usr/bash", "-c", "executable > filename.txt") creates an empty file.
exec("/usr/bash", "-c", "executable -o filename.txt") does not create a file.
One or both of the above gives an exit code of 255 when you look at it.
When you run the command from the command line as executable -o filename.txt or executable > filename.txt it works as expected.
In the light of the above, I think that the most likely cause is that /bin/bash is not finding the executable when you launch it from Java. The fact that the first example does create an empty file means that /bin/bash is doing something. But if you try to run
$ unknown-command > somefile.txt
from a bash shell prompt you will get an error message saying that the command cannot be found and an empty "something.txt" file. (You would not see the error message in your Java app because it is being written to stderr, and you are not capturing it.) The reason that the empty "something.txt" file is created is that it is opened by the shell before it attempts to fork and exec the "executable".
If this is the problem, then the simple solution is to use the absolute pathname for the executable.
Also, if you are not doing any command line redirection or other shell magic, there is no need to run the executable in a new bash instance. Rather, just do this:
Process p = Runtime.getRuntime().exec("executable", "-o", filename.txt");
then wait for the process to complete and check the exit code before trying to read the file contents.

Running other programs from Java

I need to run a couple of other programs from my own Java program, basically I need to run these command line statements.
svn log --xml -v > svn.log
and
java -jar example.jar arg1 arg2
and I need to use the text outputs written to the console from these programs in my own program. I've tried Runtime.getRuntime().exec() with the svn, but it doesn't seem to be doing anything because it doesn't make a svn.log file. Also both programs need to be called in different places, the svn line needs to be called from inside one folder and the java line needs to be called from another.
Any ideas on how to go about this? If this is not possible in Java, is there a way to do it in C#?
Thanks

Here:
ProcessBuilder processbuilder
try
{
processbuilder.directory(file);
processbuilder.redirectErrorStream(true);
process = processbuilder.start();
String readLine;
BufferedReader output = new BufferedReader(new InputStreamReader(process.getInputStream()));
// include this too:
// BufferedReader output = new BufferedReader(new InputStreamReader(process.getErrorStream()));
while((readLine = output.readLine()) != null)
{
m_Logger.info(readLine);
}
process.waitFor();
}
I've used something similar. You'll actually want to do something with the readLine. I just copied and pasted from code where I didn't care what it said.

The redirection > (like the pipe |) is a shell construct and only works when you execute stuff via /bin/sh (or equivalent). So the above isn't really going to work. You could execute
/bin/sh -c "svn log --xml -v > svn.log"
and read svn.log.
Alternatively, you can read the output from the process execution and dump that to a file (if you need to dump it to a file, or just consume it directly as you read it). If you choose this route and consume stdout/stderr separately, note that when you consume the output (stdout), you need to consume stderr as well, and concurrently, otherwise buffers will block (and your spawned process) waiting for your process to consume this. See this answer for more details.

instead of piping in your command, just let it print to standard output and error output. You can access those streams from your process object that is returned from exec.

For the svn stuff use java SVNKit API.

Seeing your two commands, why don't you do it directly from Java, without executing ? You could use SVNKit for the svn part, and include directly the jars in your classpath.

Try this
public static void main(String[] args) {
try {
// Execute a command with an argument that contains a space
System.out.println(args[0]);
String[]commands = new String[]{"svn", "info", args[0]};
Process process = Runtime.getRuntime().exec(commands);
BufferedReader reader = new BufferedReader(new InputStreamReader(process.getInputStream()));
StringBuilder builder = new StringBuilder();
String line = null;
while ((line = reader.readLine()) != null) {
builder.append(line);
builder.append(System.getProperty("line.separator"));
}
String result = builder.toString();
System.out.println(result);
}catch(Exception e){
System.out.print(e);
}
}