How do I redirect output of a shell script using Java?

Question

I am trying to use Java to execute a shell script in Linux(Ubuntu) and trying to redirect the output to another file.

String cmd[] = {"sh", "-c", "my_dir/script.sh > new_dir/out.txt"};
Process pb = Runtime.getRuntime().exec(cmd);

However this us not working properly. I am not able to get the output to be stored in the out.txt file. Could someone suggest a way to do this properly?

does new_dir already exist?

Henry
– Henry

2018-03-05 06:54:26 +00:00
Commented Mar 5, 2018 at 6:54 — Henry
– Henry, Commented Mar 5, 2018 at 6:54
permission to execute the script?

Abhishek Gangadhar
– Abhishek Gangadhar

2018-03-05 06:54:29 +00:00
Commented Mar 5, 2018 at 6:54 — Abhishek Gangadhar
– Abhishek Gangadhar, Commented Mar 5, 2018 at 6:54
@Henry Yes it exists

Abhishek Gangadhar
– Abhishek Gangadhar

2018-03-05 06:54:50 +00:00
Commented Mar 5, 2018 at 6:54 — Abhishek Gangadhar
– Abhishek Gangadhar, Commented Mar 5, 2018 at 6:54

Elliott Frisch · Accepted Answer · 2018-03-05 06:53:53Z

2

Use a ProcessBuilder. I don't see a need for spawning an extra sh. Something like,

ProcessBuilder pb = new ProcessBuilder("my_dir/script.sh");
pb.redirectOutput(new File("new_dir/out.txt"));
Process p = pb.start();

should be all you need.

answered Mar 5, 2018 at 6:53

Elliott Frisch

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3 Comments

Abhishek Gangadhar Over a year ago

Suppose I want to also print the output of the script file as well at the same time, how would I go about doing that?

daniu Over a year ago

@AbhishekGangadhar Your question was how to do the shell redirect. Are you instead asking how to read process output using Java?

Abhishek Gangadhar Over a year ago

@Elliott Frisch How world I use tee command with Process Builder?

SYAM KRISHNA MG · Accepted Answer · 2018-03-05 06:57:33Z

1

This worked for me. Use Runtime.exec()

    Process p = Runtime.getRuntime().exec("my_dir/script.sh > new_dir/out.txt");
    // Wait for execution completion 
    p.waitFor();

answered Mar 5, 2018 at 6:57

SYAM KRISHNA MG

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