I need to start a server using bash, so I had created an UNIX shell , but I am not able to execute it with Java from Eclipse.
I tried the following code which doesn't work :
Process proc = Runtime.getRuntime().exec(./startServer);
Here is content of the startServer file :
#!/bin/bash
cd /Users/sujitsoni/Documents/bet/client
npm start
You can try the following two options.
Option 1
Process proc = Runtime.getRuntime().exec("/bin/bash", "-c", "<Abosulte Path>/startServer");
Option 2
ProcessBuilder pb = new ProcessBuilder("/bin/bash", "-c", "<Absolute Path>/startServer");
pb.directory(new File("<Absolute Path>"));
Process proc = pb.start();
A couple Of things can go wrong:
The path to the file you have given might be wrong for eclipse it can take relative path but from the command line, it will take the absolute path.
error=13, Permission denied - If the script file doesn't have required permissions. In your scenario, that might not the case as you are not getting any error.
At last, you are executing the script by java program so the output of your script will not be printed out. In your scenario, this might be the case. You need to capture the output of script from BufferedReade and print it. ( In your case server might have started but you are not seeing the logs/output of the script.
See the code sample below for printing output.
public static void main(String[] args) throws IOException, InterruptedException {
Process proc = Runtime.getRuntime().exec("./startServer");
proc.waitFor();
StringBuffer output = new StringBuffer();
BufferedReader reader = new BufferedReader(new InputStreamReader(proc.getInputStream()));
String line = "";
while ((line = reader.readLine()) != null) {
output.append(line + "\n");
}
System.out.println(output);
}
Related
I'm looking a way to write running log of python which is executed by java app via script.
Let's say my script is:
import time
for x in range(120):
print("Running ", x)
time.sleep(1)
Here is my current solution:
Trigger script using java
String cmd = "python script.py";
var process = Runtime.getRuntime().exec(cmd, null, new File(sandboxPath));
Write log to new file:
String traceLogCmd = String.format("strace -p %s -s 9999 -e trace=write -o output.txt", process.pid());
Runtime.getRuntime().exec(traceLogCmd, null, new File(sandboxPath));
Now the problem is output.txt only has content whenever the python script is done executing so that I cannot tailf the output file.
Meanwhile if I execute python script.py and strace command dirrectly from terminal, the output is exactly what I expected.
Can someone correct me if I did something wrong or have a another way to get python log?
Thanks in advance.
Use ProcessBuilder instead of Runtime.exec(). More details: When Runtime.exec() won't
The following code will append to StringBuilder object output of the script sb.append(line);. It would not be difficult to write that content to a file.
Process p = new ProcessBuilder("sh", "-c", "python", "path-to-your-script").start();
String result = getCommandResult(p.getInputStream());
private static String getCommandResult(InputStream stream) throws IOException {
StringBuilder sb = new StringBuilder();
try (InputStreamReader isr = new InputStreamReader(stream);
BufferedReader in = new BufferedReader(isr)) {
String line;
while ((line = in.readLine()) != null) {
sb.append(line);
}
}
return sb.toString().trim();
}
I want to read output from ADB logcat (https://developer.android.com/studio/command-line/adb). I have such code (test):
try {
Process p = Runtime.getRuntime().exec("sh -c adb logcat");
BufferedReader bufferedReader = new BufferedReader(new InputStreamReader(p.getInputStream()));
while(true) {
String s = bufferedReader.readLine();
if(s == null) {
continue;
}
System.out.println("From process: " + s);
}
} catch (IOException e) {
e.printStackTrace();
}
But this prints nothing. If I execute this:
Process p = Runtime.getRuntime().exec("sh -c ls");
It works.
Okay, I too fast asked the question on SO.
I read error stream instead of inputstream and I find out that cannot find program ADB. Need to provide full path:
ProcessBuilder processBuilder = new ProcessBuilder("/home/UserName/Soft/Android/Sdk/platform-tools/adb", "logcat");
BufferedReader bufferedReader = new BufferedReader(new InputStreamReader(p.getInputStream()));
But on another computer path is different. Also you can on every computer make symbolic link and in code use as path simply "adb":
sudo ln -s /home/UserName/Soft/Android/Sdk/platform-tools/adb /bin/adb
ProcessBuilder processBuilder = new ProcessBuilder("adb", "logcat");
This is not the best solution, partially resolves problem. Would be great without making symbolic link, using simply "adb" in instantiating ProcessBuilder object. Because in every disk location on my computer I can use ADB in terminal, it is visible but in this code no. In Windows I know that this is in System Environments > PATH. In linux I wrote command "printenv" but I don't see anything with android & adb.
I'm trying to run a shell script from Java (using Runtime.getRuntime().exec(cmd)). All commands in the script file seem to be running normally except the angular-cli (ng) commands.
My Java File:
System.out.println("Executing Script...");
final String[] cmd = new String[]{"/bin/bash", "test.sh"};
final Process process = Runtime.getRuntime().exec(cmd);
process.waitFor();
final BufferedReader reader = new BufferedReader(new InputStreamReader(process.getInputStream()));
String s;
while ((s = reader.readLine()) != null) {
System.out.println("Script output: " + s);
}
process.destroy();
System.out.println("Script Executed.");
test.sh:
#!/bin/bash
cd ~/ &&
ng new newAngularProject &&
Outout:
Executing Script...
Script Executed.
No errors are thrown. All other commands work but for some reason, I'm unable to run ng commands. Also, I've tested the file w/o running it from Java - When I run the same script directly on the console, it works perfectly and all commands (including ng commands) work neatly. I'm running on MacOS in case you wanted to know.
Also print the error stream. You will get the error message, if it is there.
final BufferedReader errorReader = new BufferedReader(new InputStreamReader(process.getErrorStream()));
while ((s = errorReader.readLine()) != null) {
System.out.println("error: " + s);
}
Also you can try to use absolute path of ng in your test.sh e.g. /home/my/install/node-vxxx/ng, since the process spawn by java to run your command might not get the environment variable you set in your .bashrc /.bash_aliases
When I run a bach script containing "echo $Path" command what it outputs when run by java is different from what it outputs when run from command line. It also affects other commands of my script. Why is this happening and how do I avoid?
Following is my function to run a bashscript
public static String executeCommands(File tempScript, Boolean deleteFile)
throws IOException, InterruptedException {
StringBuffer output = new StringBuffer();
try {
ProcessBuilder pb = new ProcessBuilder("bash", tempScript.toString());
pb.inheritIO();
Process process = pb.start();
process.waitFor();
BufferedReader reader =
new BufferedReader(new InputStreamReader(process.getInputStream()));
String line = "";
while ((line = reader.readLine()) != null) {
output.append(line + "\n");
}
return line;
} finally {
if (deleteFile == true)
tempScript.delete();
}
}
when the script contains "echo $PATH" in bashscript
output is
/usr/bin:/bin:/usr/sbin:/sbin
But when I run from commandline output is
/usr/local/bin:/usr/bin:/bin:/usr/sbin:/sbin:/usr/local/scala/scala-2.11.8/bin:/Users/<user>/Installations/activator-dist-1.3.10
When we run the command from terminal it reads the environment variables from .bashrc file, but it seems eclipse does not read environment variables from .bashrc.
launch eclipse with ./eclipse -DPATH=$PATH to read from bashrc
PATH variable from
1.terminal
user#ubuntu:~$ javac SS47.java
user#ubuntu:~$ java SS47
/home/user/perl5/bin:/usr/local/sbin:/usr/local/bin:/usr/sbin:/usr/bin:/sbin:/bin:/usr/games:/usr/local/games:/home/user/apache-maven-3.3.3/bin:/home/user/apache-maven-3.3.3/bin:/opt/jdk/jdk1.8.0_60/bin:/opt/jdk/jdk1.8.0_60/jre/bin:/home/user/dsc-cassandra-2.1.6/bin:/home/user/hadoop-2.6.0/bin:/home/user/hadoop-2.6.0/sbin:/home/user/android/android-studio/bin:/home/user/android/android-sdk-linux/platform-tools:/home/user/elasticsearch-2.3.5/bin:/home/user/scala-2.11.8/bin::/home/user/apache-maven-3.3.3/bin
2.eclipse with out $PATH
/usr/local/sbin:/usr/local/bin:/usr/sbin:/usr/bin:/sbin:/bin:/usr/games:/usr/local/games
3.eclipse with PATH ./eclipse -DPATH=$PATH
/home/user/perl5/bin:/usr/local/sbin:/usr/local/bin:/usr/sbin:/usr/bin:/sbin:/bin:/usr/games:/usr/local/games:/home/user/apache-maven-3.3.3/bin:/home/user/apache-maven-3.3.3/bin:/opt/jdk/jdk1.8.0_60/bin:/opt/jdk/jdk1.8.0_60/jre/bin:/home/user/dsc-cassandra-2.1.6/bin:/home/user/hadoop-2.6.0/bin:/home/user/hadoop-2.6.0/sbin:/home/user/android/android-studio/bin:/home/user/android/android-sdk-linux/platform-tools:/home/user/elasticsearch-2.3.5/bin:/home/user/scala-2.11.8/bin::/home/user/apache-maven-3.3.3/bin
As Elliott-Frisch pointed out in his comment, just call bash with the option -l which
Make[s] bash act as if it had been invoked as a login shell (see INVOCATION below). Source
This way you don't have to call Eclipse with different launch options etc. and it makes your solution independent, being able to be run without the non customized Eclipse or just bare-bone JRE.
So just edit your call ProcessBuilder like this:
ProcessBuilder pb = new ProcessBuilder("bash", "-l", tempScript.toString());
I am hoping to leverage the unix sort command to sort a large text file in Java. I've tried executing sort with the process builder, but with no luck. However when I print the exact command it is going to execute and copy and paste it into the terminal, it works fine.
So far I've tried executing with /bin/sh -c "", making sure the directory the input file is and where the output file will be is fully permissioned (chmod 777) but with no luck.
Here is the code (if it looks funny, note is using some functions found in Guava)
File inputFile = new File(inputFileName);
//build the command (optional number of sort columns)
List<String> command = new LinkedList<String>();
command.addAll(ImmutableList.<String>of("sort","-t"+delimiter));
for (int i : sortFieldPositions) {
command.add("-k"+i+","+i);
}
command.addAll(ImmutableList.<String>of(inputFileName,">",outputFileName));
//for debugging: output the command that will be executed
System.out.println("Executing: "+Joiner.on(" ").join(command));
//construct and start the process
Process process = new ProcessBuilder(command).redirectErrorStream(true).directory(inputFile.getParentFile()).start();
//for debugging: save process output
BufferedReader bufferedReader = new BufferedReader(new InputStreamReader(process.getInputStream()));
StringBuilder outputStringBuilder = new StringBuilder();
for (String line; (line = bufferedReader.readLine()) != null; /*reading taking place in check */) {
System.out.println("FROM PROCESS: "+line);
outputStringBuilder.append(line);
}
bufferedReader.close();
if (process.exitValue() != 0) {
//something went wrong
throw new RuntimeException("Error code "+process.exitValue()+" executing command: "+Joiner.on(" ").join(command)+"\n"+outputStringBuilder.toString());
}
Unfortunately this does not work, with the following output:
Executing: sort -t, -k2,2 -k1,1 /tmp/java/TestDataSorterImporterInput.txt /tmp/java/TestDataSorterImporterOutput.txt
FROM PROCESS: sort: stat failed: >: No such file or directory
Edit: It may be helpful to note that if I remove saving the output (> outputfile) from the command, then the command executes without complaint and the sorted version appears in the output from the Processes' input stream)
It is the shell that knows how to perform output redirection. The sort program cannot do it on its own. So if you want redirection, you need to do /bin/sh -c ... to let she shell into the loop.
(You write that you have tried this, but something else must have gone wrong with that).
Try this:
String whatever = "filename";
Process p = Runtime.getRuntime().exec("sort -t -k2 2 -k1 1 " + whatever);
See this site.
Process process = new ProcessBuilder("/bin/bash", "-c", "sort -t'|' -k2").start();