I am having trouble while running following command using apache commons exec: sysctl -n net.ipv4.neigh.default.gc_thresh3
The problem is it is giving the following error:
Exception in thread "main" java.lang.RuntimeException: Could not run command [/bin/sh, -c, sysctl, -n, net.ipv4.neigh.default.gc_thresh3]
at Testing.runCommand(Testing.java:44)
at Testing.main(Testing.java:97)
Caused by: org.apache.commons.exec.ExecuteException: Process exited with an error: 1 (Exit value: 1)
at org.apache.commons.exec.DefaultExecutor.executeInternal(DefaultExecutor.java:404)
at org.apache.commons.exec.DefaultExecutor.execute(DefaultExecutor.java:166)
at org.apache.commons.exec.DefaultExecutor.execute(DefaultExecutor.java:153)
at Testing.runCommand(Testing.java:31)
... 1 more
Below is my code:
private String runCommand(String cmd, String params) {
CommandLine commandLine = new CommandLine(cmd);
commandLine.addArguments(params);
ByteArrayOutputStream stdout = new ByteArrayOutputStream();
ByteArrayOutputStream stderr = new ByteArrayOutputStream();
PumpStreamHandler pumpStreamHandler = new PumpStreamHandler(stdout, stderr);
ExecuteWatchdog watchdog = new ExecuteWatchdog(30000); // 30s timeout
DefaultExecutor executor = new DefaultExecutor();
executor.setStreamHandler(pumpStreamHandler);
executor.setWatchdog(watchdog);
try {
int retCode = executor.execute(commandLine);
System.out.println("Executed '" + cmd + "'\n"
+ "returnCode: " + retCode + "\n"
+ "stdout:\n" + stdout.toString() + "\n"
+ "stderr:\n" + stderr.toString());
if (retCode == 0) {
return stdout.toString();
} else {
throw new NonZeroExitStatusReturnedException(commandLine.toString(), retCode);
}
} catch (IOException e) {
throw new RuntimeException("Could not run command "+ commandLine.toString(), e);
}
}
I am using the cmd - /bin/sh
and params - -c sysctl -n net.ipv4.neigh.default.gc_thresh3
.
How can i run commands like that without facing such kind of error using apache commons exec?
I dont need the complete solution. Any good direction is fine with me.
The problem is /bin/sh
is not the proper path to run this kind of command. The command should be executed in: /sbin/sysctl
.
Also, different operating system requires different path to run. see man sysctl
So, the cmd is - /sbin/sysctl
and params - new String[] { "-n", "net.ipv4.neigh.default.gc_thresh3" }
The code will look like this:
private String runCommand(String cmd, String[] params) {
CommandLine commandLine = new CommandLine(cmd);
commandLine.addArguments(params, false);
ByteArrayOutputStream stdout = new ByteArrayOutputStream();
ByteArrayOutputStream stderr = new ByteArrayOutputStream();
PumpStreamHandler pumpStreamHandler = new PumpStreamHandler(stdout, stderr);
ExecuteWatchdog watchdog = new ExecuteWatchdog(30000); // 30s timeout
DefaultExecutor executor = new DefaultExecutor();
executor.setStreamHandler(pumpStreamHandler);
executor.setWatchdog(watchdog);
try {
int retCode = executor.execute(commandLine);
System.out.println("Executed '" + cmd + "'\n"
+ "returnCode: " + retCode + "\n"
+ "stdout:\n" + stdout.toString() + "\n"
+ "stderr:\n" + stderr.toString());
if (retCode == 0) {
return stdout.toString();
} else {
throw new NonZeroExitStatusReturnedException(commandLine.toString(), retCode);
}
} catch (IOException e) {
throw new RuntimeException("Could not run command "+ commandLine.toString(), e);
}
}