string logFileName = "myapp.log"; string logDirectory = "/var/log/myapp/"; string logFilePath = Path.Combine(logDirectory, logFileName);In this example, the Path.Combine method is used to build the full file path by concatenating the log directory and file name strings. The resulting value of logFilePath will be "/var/log/myapp/myapp.log" on Unix-like systems, and "C:\var\log\myapp\myapp.log" on Windows. The package library for FilePath Build is part of the .NET Standard Library, which is a set of APIs that are available across all .NET implementations.