Java Tutorials and Guides
CSS Tutorials and Guides
Java - Execute Shell Command Using Runtime.exec
1. Description
Runtime.exec (String command) - This function provides the ability to execute the command provided in the arguments in a separate process.
2. Declaration
public Process exec(String command)
3. Parameters
command - the command to be executed
4. Return value
This method returns a process object
5. Implementation
In this example, we will execute the ls -l / command to list all the directories present in the home folder and display their permissions.
import java.io.BufferedReader;
import java.io.IOException;
import java.io.InputStreamReader;
public class ExecuteShellCommandRuntimeExec {
public static void main (String [] args) {
try {
Process process = Runtime.getRuntime().exec("ls -l");
StringBuilder output = new StringBuilder();
BufferedReader reader = new BufferedReader(new InputStreamReader (process.getInputStream()));
String line;
while((line = reader.readLine()) != null) {
output.append(line + "\n");
}
int exitVal = process.waitFor();
if (exitVal == 0) {
System.out.println("Success");
System.out.println(output);
System.exit(0);
} else {
System.out.println("Something abnormal has haapened :( ");
}
} catch (IOException e) {
e.printStackTrace();
} catch (InterruptedException e) {
e.printStackTrace();
}
}
}
Output:
vpn-133-230-1-200:~ softorks$ ls -l /
total 13
drwxrwxr-x+ 81 root admin 2592 Oct 17 11:02 Applications
drwxr-xr-x+ 69 root wheel 2208 Aug 21 12:47 Library
drwxr-xr-x 3 root wheel 96 Oct 17 10:44 Network
drwxrwx--- 203 root Virex 6496 Oct 15 19:37 Quarantine
drwxr-xr-x@ 5 root wheel 160 May 4 01:21 System
drwxr-xr-x 6 root admin 192 Jun 22 11:32 Users
drwxr-xr-x@ 4 root wheel 128 Oct 17 10:48 Volumes
drwxr-xr-x@ 37 root wheel 1184 Oct 13 05:40 bin
drwxrwxr-t 2 root admin 64 Jun 22 11:32 cores
dr-xr-xr-x 3 root wheel 4349 Oct 17 10:44 dev
lrwxr-xr-x@ 1 root wheel 11 Jun 22 11:31 etc -> private/etc
dr-xr-xr-x 2 root wheel 1 Oct 17 11:32 home
-rw-r--r-- 1 root wheel 313 Feb 24 2019 installer.failurerequests
dr-xr-xr-x 2 root wheel 1 Oct 17 11:32 net
drwxr-xr-x@ 3 root wheel 96 Dec 9 2016 opt
drwxr-xr-x 7 root wheel 224 Aug 21 12:47 private
drwxr-xr-x@ 64 root wheel 2048 Oct 13 05:40 sbin
lrwxr-xr-x@ 1 root wheel 11 Jun 22 11:31 tmp -> private/tmp
drwxr-xr-x@ 9 root wheel 288 May 4 01:14 usr
lrwxr-xr-x@ 1 root wheel 11 Jun 22 11:31 var -> private/var
6. traceroute Example
In this example, we will execute the traceroute command to show all the IP addresses of all the network nodes between a source and a destination.
import java.io.BufferedReader;
import java.io.IOException;
import java.io.InputStreamReader;
public class ExecuteShellCommandRuntimeExec {
public static void main (String [] args) {
try {
Process process = Runtime.getRuntime().exec("traceroute google.com");
StringBuilder output = new StringBuilder();
BufferedReader reader = new BufferedReader(new InputStreamReader (process.getInputStream()));
String line;
while((line = reader.readLine()) != null) {
output.append(line + "\n");
}
int exitVal = process.waitFor();
if (exitVal == 0) {
System.out.println("Success");
System.out.println(output);
System.exit(0);
} else {
System.out.println("Something abnormal has haapened :( ");
}
} catch (IOException e) {
e.printStackTrace();
} catch (InterruptedException e) {
e.printStackTrace();
}
}
}
Output:
vpn-133-230-1-200:~ softorks$ traceroute softorks.com
traceroute to softorks.com (162.241.252.212), 64 hops max, 52 byte packets
1 www.routerlogin.com (192.168.1.1) 1.828 ms 1.171 ms 1.076 ms
2 96.120.5.17 (96.120.5.17) 10.819 ms 9.734 ms 10.236 ms
3 68.86.108.157 (68.86.108.157) 9.466 ms 10.106 ms 11.188 ms
4 ae-127-ar01.b0atlanta.ga.atlanta.comcast.net (68.85.111.57) 10.193 ms 17.725 ms 10.128 ms
5 be-7725-cr02.56marietta.ga.ibone.comcast.net (68.86.93.125) 13.317 ms 12.365 ms *
6 be-11423-cr01.houston.tx.ibone.comcast.net (68.86.85.22) 30.680 ms 25.503 ms 25.118 ms
7 be-12393-pe01.westwaypark.tx.ibone.comcast.net (68.86.82.130) 25.743 ms 24.762 ms 25.539 ms
8 as8075-1.2001sixthave.wa.ibone.comcast.net (75.149.230.54) 25.087 ms 25.201 ms 25.575 ms
9 216.117.50.150 (216.117.50.150) 25.742 ms 26.621 ms 25.381 ms
10 po101.router2b.hou1.net.unifiedlayer.com (162.241.0.9) 25.678 ms 25.893 ms
po101.router2a.hou1.net.unifiedlayer.com (162.241.0.7) 25.370 ms
11 162-241-150-61.unifiedlayer.com (162.241.150.61) 26.501 ms
162-241-150-59.unifiedlayer.com (162.241.150.59) 25.636 ms *
12 box5741.bluehost.com (162.241.252.212) 28.384 ms 26.011 ms 24.808 ms