Mathematica provides a convenient collection of platform-independent functions for manipulating names of files and directories. These functions can also be used to assemble and disassemble file-name-like constructs such as URLs.
FileNameSplit — split a file name into directory and name parts
FileNameJoin — assemble a file name from a list of components
FileNameTake,
FileNameDrop — take, drop elements from a file name
ExpandFileName — textually expand to absolute file name form
AbsoluteFileName — determine the absolute name for a file in your filesystem
DirectoryQ — test whether a name corresponds to an existing directory
FileNames — list names of files or directories on your computer system
FileExistsQ — test whether a file exists on your computer system
FindFile — find a file on
$Path, etc.
FileNameSetter — interactively browse for a file
