CODEWITHSUNDEEP
java
akhila
akhila

Reputation: 35

How to run unix / shell commands with wildcards using Java?

I want to run some unix/shell commands in Java and process the output. I used getRuntime.exec(), but it is not giving correct output for some commands like ls directory_path/*.tar.gz . For that command my program is not giving any output but it is giving error saying No such file or directory. But the same command is giving correct output on command prompt.

Is there any other way to execute commands which include wildcards in Java?

Upvotes: 2

Views: 3525

Answers (3)

aioobe
aioobe

Reputation: 421080

Is there any other way to execute commands which include wildcards in Java?

Yes there is.

You have three potential problems in your code:

  1. Assuming you want to see the output of the external command you need to take care of the output it produces, and print it yourself.

    Follow the example I've provided over here:

  2. The shell expansion of * doesn't work if you naively go through Runtime.exec.You have to go through /bin/bash explicitly.

  3. If you try to list the content of directory_path/*.tar.gz you should know that (if you're not starting with a /) directory_path will be resolved relative to the current working directory. Try at first to give the absolute path to make sure it works, and then try to figure out why it can't find the relative path.

Here's a complete example that should work:

Process proc = new ProcessBuilder("/bin/bash", "-c",
                                  "ls /.../directory_path/*.tar.gz").start();

Reader reader = new InputStreamReader(proc.getInputStream());
int ch;
while ((ch = reader.read()) != -1)
    System.out.print((char) ch);
reader.close();

Upvotes: 6

CyberDem0n
CyberDem0n

Reputation: 15046

"ls directory_path/*.tar.gz" works relative to CURRENT directory.

Upvotes: 0

Martijn Courteaux
Martijn Courteaux

Reputation: 68877

That is because you specified a relative path to the directory and your application is running in a working directory. The path you specified is relative to that working directory.

To find out what the absolute path is, you can check out the working directory.

System.out.println("Working directory: " + System.getProperty("user.dir"));

Upvotes: 0

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