org.paneris.util
Class SystemUtils

java.lang.Object
  org.paneris.util.SystemUtils

public class SystemUtils
extends java.lang.Object

This class contains a number of static functions to run commands in new processes

Constructor Summary

SystemUtils()

Method Summary

static java.lang.String	exec(java.lang.String cmd) Execute a system command and return its ouput in a String.
static java.lang.String	execAsScript(java.lang.String script, java.lang.String scriptName) Write a command to a script and then execute that script.

Methods inherited from class java.lang.Object

clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait

Constructor Detail

SystemUtils

public SystemUtils()

Method Detail

exec

public static java.lang.String exec(java.lang.String cmd)
                             throws java.io.IOException

Execute a system command and return its ouput in a String.

It works by forking a separate process and capturing it's output stream (which is a java.lang.io.InputStream!)

Note that at present we ignore any InterruptedException which might get thrown whilst we are waiting for the process to terminate

Parameters:

cmd - System command to execute

Returns:

the command's output

Throws:

java.io.IOException - if there is a problem reading from the process' output stream

See Also:

InputStream, Process

execAsScript

public static java.lang.String execAsScript(java.lang.String script,
                                            java.lang.String scriptName)
                                     throws java.io.IOException

Write a command to a script and then execute that script. This can be used, for instance, to change the working directory before calling a command by using something like cmd = "#/bin/sh \n\n cd /some/where; ls"

If the script is not executable then this will fail silently. IT IS UP TO YOU TO MAKE THE FILE EXECUTABLE ON YOUR SYSTEM. YOU MUST ALSO MAKE THE CMD AN APPROPRIATE SCRIPT

TODO - can we chmod in Java?

Parameters:

script - text of a script to execute

scriptName - the filename to write the script to. The file should be executable (you might want to create it before hand and change permissions outside of java)

Returns:

output of the script

Throws:

java.io.IOException - if there is a problem reading from the script's output stream