Run linux command in java to send email with quotes

Question

I am able to send emails in Linux via commandline:

cat < x.txt | mail -s "SUBJECT" email@email.com

This works perfectly. Note: The body is in x.txt.

Now, I want to execute exactly this command with Java.

Process p = Runtime.getRuntime().exec(
            new String[] { "cat < x.txt", "|", "mail -s", "SUBJECT",
                    "email@email.com" });

    p.waitFor();
    BufferedReader buf = new BufferedReader(new InputStreamReader(
            p.getInputStream()));
    String line = "";
    String output = "";

    while ((line = buf.readLine()) != null) {
        output += line + "\n";
    }

System.out.println(output);

Well, It is not working and I am getting following error.

Exception in thread "main" java.io.IOException: Cannot run program "cat < x.txt |": error=2, Datei oder Verzeichnis nicht gefunden
        at java.lang.ProcessBuilder.start(ProcessBuilder.java:1048)
        at java.lang.Runtime.exec(Runtime.java:620)
        at java.lang.Runtime.exec(Runtime.java:485)
        at test.main(test.java:9) Caused by: java.io.IOException: error=2, Datei oder Verzeichnis nicht gefunden
        at java.lang.UNIXProcess.forkAndExec(Native Method)
        at java.lang.UNIXProcess.<init>(UNIXProcess.java:248)
        at java.lang.ProcessImpl.start(ProcessImpl.java:134)
        at java.lang.ProcessBuilder.start(ProcessBuilder.java:1029)
        ... 3 more

Am I splitting those command(s) wrong?

How can I execute this command properly?

why 'cat < x.txt' rather than just 'cat x.txt' ? – Marc Q. Dec 16 '15 at 15:33 — Marc Q., Dec 16 '15 at 15:33

EvenLisle · Accepted Answer · 2015-04-18T11:58:06.013

6

Try to write a script and execute it, rather than execute separate commands:

String email = "email@email.com"; // Or any way of entering the email address
String[] command = {"/bin/sh", "-c", "cat < x.txt | mail -s SUBJECT" +  email};
Process p = Runtime.getRuntime().exec(command);

Pipe (|) is a shell built-in, and not an actual unix command as such.

edited Apr 18 '15 at 11:58

answered Apr 18 '15 at 11:29

EvenLisle

4,672
3
24
47

Okay, thank you for the hint. Unfortunately I need to pass the email as param from java. Is there any chance to do this? – alexander Apr 18 '15 at 11:54
So sorry, I didn't change the code to fit your example. Updated the answer. – EvenLisle Apr 18 '15 at 11:59
Well, no one said that. I asked about any chance, not about code. A hint was enough. Well, I found an other solution, without pipe. Thanks anyway, you opened my eyes! :) And sorry, I am not familiar with linux and those commands. – alexander Apr 18 '15 at 14:03

score 0 · Answer 2 · answered Apr 18 '15 at 11:29

You should probably be doing something like:

Process p = Runtime.getRuntime().exec("/usr/sbin/sendmail .. email@email.com");
OutputStream os = p.getOutputStream();
InputStream is = new FileInputStream("x.txt");
// copy the contents
byte[] buf = new byte[4096];
int len;
while ((len = is.read(buf)) != -1) {
    os.write(buf, 0, len); // only write as many as you have read
}
os.close();
is.close();

Also note, you have javamail api already available, so make sure you make your code platform independent by using such libraries.

Run linux command in java to send email with quotes

2 Answers2