Runtime.getRuntime().exec strange behavior

Question

I am trying to call a perl script from java runtime. It worked fine on my windows7 laptop with the following code,

try {
    String cmdString= "c:\\perl64\\bin\\perl.exe c:\\perl64\\eg\\userinput.pl \""+arg1+"\" \""+arg2+"\"";
    Process p = Runtime.getRuntime().exec(cmdString);
} catch(IOException e) {
    System.out.println(e);
}

The perl script runs and produces what I expect (update database).

When I move the whole thing over to a remote CentOS server, it doesn't work anymore. The script is the same and the java code is,

try {
    String cmdString= "/opt/lampp/bin/perl /home/support/scripts/userinput.pl \""+arg1+"\" \""+arg2+"\" > /tmp/userinput.log";
    log(cmdString);
    Process p = Runtime.getRuntime().exec(cmdString);
} catch(IOException e) {
    System.out.println(e);
}

I added redirect to /tmp/userinput.log after I see the script is not working. But there is no log file created at all. I also added log to make sure this part of the java code did get executed, and indeed it did. I also tried to add "/bin/bash " in front of the comString and it didn't make a difference. However, when I run the cmdString directly on the remote server from command line, it works without problem.

Now, when I changed the cmdString to "touch /tmp/userinput.log", it does create the empty log file.

So I know the Runtime.getRuntime().exec(cmdString) command ran, and the cmdString works when entered on command line, and a simple "touch" command would work with this setup. But I am totally lost why the actual cmdString that calls the perl script doesn't work, and there is no message whatsoever to tell me what is wrong.

Can someone please help?

Answer 1

Frist, separate each parameter for the command and use the version of exec which takes a String[] (you won't have to worry about quoting issues). also, shell redirection won't work since java isn't executing a shell.