Improve company productivity with a Business Account.Sign Up

x
  • Status: Solved
  • Priority: Medium
  • Security: Public
  • Views: 639
  • Last Modified:

Java RunTime exec method's Usage

Hi; I try to use run following script by Runtime.getRuntime.exec. But I do not know how to write arguments.

String[] cmdArray = new String[]{"ps","awk","sort","uniq","awk","grep"};
String[] parameters = new String[]{"aux", "'{print $4 \"\\t\"$11}'"....",null,"-c","'{print $2\" \"$1\" \"$3}'","java"};
       
Process proc = Runtime.getRuntime.exect(cmdArray,parameters);

Am I right?

ps aux | awk '{print $4"\t"$11}' | sort | uniq -c | awk '{print $2" "$1" "$3}' | grep java
0
JianJunShen
Asked:
JianJunShen
  • 7
  • 4
  • 2
  • +1
3 Solutions
 
a_bCommented:
What is the error/issue that occurs when you run this? looks okay to me.
0
 
CEHJCommented:
With a command as complex as that, you would be much better advised to put it in a shell script and Runtime.exec that

But see

http://www.javaworld.com/javaworld/jw-12-2000/jw-1229-traps.html
0
 
CEHJCommented:
That would be


String[] args = { "/bin/bash", "x.sh" };
Process p = Runtime.getRuntime().exec(args);

Open in new window

0
Keep up with what's happening at Experts Exchange!

Sign up to receive Decoded, a new monthly digest with product updates, feature release info, continuing education opportunities, and more.

 
JianJunShenAuthor Commented:
where shall I put script file(x.sh)?

String[] args = { "/bin/bash", "x.sh" };
Process p = Runtime.getRuntime().exec(args);
0
 
CEHJCommented:
Well a safe place would be in your home directory
0
 
JianJunShenAuthor Commented:
well, if one use eclipse, it is better to put in project root directory. Pararel to src folder.
0
 
CEHJCommented:
:-)

btw, my comment at http:#24850675 is devoted to getting output
0
 
nkiggsCommented:
Hi,

To run complex commands you can simulate your multiple command line arguments with a bufferedwriter writing to the shell you create. So you will have all the commands like:

/bin/sh
cd ..
pwd
exit

to create a shell(or you can use /bin/csh) go one directory backwards(cd ..) and then finally print the working directory (pwd) and finally exit (exit) after reading with the bufferedreader output from pwd command. Code example below to do this. Alter to suite the order you would type your commands in your shell script.
  	public int runProcess(){
      	// code to commence processing		
		String line;
		File wd = new File("/bin");	//location of sh executable 
		Process proc = null; 
		
		try { 
			proc = Runtime.getRuntime().exec("/bin/sh", null, wd); 
		} 
		catch (IOException e) { 
			e.printStackTrace(); 
		} 
		
		if (proc != null) { 
			BufferedReader in = new BufferedReader(new InputStreamReader(proc.getInputStream())); 
			PrintWriter out = new PrintWriter(new BufferedWriter(new OutputStreamWriter(proc.getOutputStream())), true); 
			out.println("cd ..");	
			out.println("pwd");				
			out.println("exit"); 
			try { 	
				int x = 0;
				while ((line = in.readLine()) != null) { 
					if (x > -1){
						System.out.println(line + "\n");
					}
					x++;				
				} 
				proc.waitFor(); 
				in.close(); 
				out.close(); 
				proc.destroy(); 
			} 
			catch (Exception e) { 
				e.printStackTrace(); 
			} 
		}      		
   	}

Open in new window

0
 
nkiggsCommented:
Hi,

You can simulate all the commands you will normally enter into your shell script window by using both BufferedReader and BufferedWriter simultaneously. Therefore, your application would operate as if you are entering commands manually (BufferedWriter) and get all the output as you enter commands (BufferedReader).

This output can be manipulated with a variable x that tracks the number of lines outputed and you can use this output by manipulating the string "line".

See my comment on the question.

Regards,

nkiggs
0
 
CEHJCommented:
nkiggs probably didn't intend to object i'd guess
0
 
JianJunShenAuthor Commented:
I think ID:24867139 is the best solution.       ID:24850700 is assistant answer. It is also a good one.
0
 
JianJunShenAuthor Commented:
Experts answer are excellent.
0
 
CEHJCommented:
The late addition is only appropriate when you for some reason want to run an interactive shell from within Java, which was certainly not mentioned as a requirement...
0
 
CEHJCommented:
*Is* it a requirement JianJunShen?
0
Question has a verified solution.

Are you are experiencing a similar issue? Get a personalized answer when you ask a related question.

Have a better answer? Share it in a comment.

Join & Write a Comment

Featured Post

Free Tool: Port Scanner

Check which ports are open to the outside world. Helps make sure that your firewall rules are working as intended.

One of a set of tools we are providing to everyone as a way of saying thank you for being a part of the community.

  • 7
  • 4
  • 2
  • +1
Tackle projects and never again get stuck behind a technical roadblock.
Join Now