Q:

How to find a user's home directory on linux or unix?

How do I find the home directory of an arbitrary user from within Grails?  On Linux it's often /home/user.  However, on some OS's, like OpenSolaris for example, the path is /export/home/user.

A:

Normally you use the statement
String userHome = System.getProperty( "user.home" );

to get the home directory of the user on any platform. See the method documentation for getProperty to see what else you can get. 
There may be access problems you might want to avoid by using this workaround (Using a security policy file)

A:

For UNIX-Like systems you might want to execute "echo ~username" using the shell (so use Runtime.exec() to run {"/bin/sh", "-c", "echo ~username"}).

A:

Try this on Java:
System.out.println("OS: " + System.getProperty("os.name") + ", USER DIRECTORY: " + System.getProperty("user.home"));

