Changing the working directory of a subprocess
Often, you'll want a process to be executed in the context of a path, such as listing the files in a directory. To do so, we will have to tell ProcessBuilder to launch the process in the context of a given location. We can achieve this by using the directory() method. This method serves two purposes: 
- It returns the current directory of execution when we don't pass any parameters.
- It sets the current directory of execution to the passed value when we pass a parameter.
In this recipe, we will see how to execute theÂ
tree command to recursively traverse all the directories from the current directory and print it in the form of a tree. 
Getting ready
Generally, the tree command doesn't come preinstalled, so you will have to install the package that contains the command. To install on an Ubuntu/Debian-based system, run the following command:
$ sudo apt-get install treeTo install on Linux, which supports the yum package manager, run the following command...
 
             
             
             
             
             
             
             
             
             
             
             
             
             
             
             
             
             
             
             
             
             
             
             
             
             
             
             
             
             
             
             
             
             
             
             
             
             
             
             
             
             
             
             
             
             
             
             
             
             
             
             
             
             
             
     
         
                 
                 
                 
                 
                 
                 
                 
                 
                 
                 
                 
                 
                 
                 
                 
                 
                 
                 
                 
                 
                