Directory — current kernel directory

SetDirectory — set the current kernel directory

NotebookDirectory — current notebook directory

ResetDirectory  ▪  DirectoryStack

Directory Names »

ParentDirectory — the parent of a directory

DirectoryName — pick out the directory part from a full file name

FileNameJoin — assemble a file name from a list of parts

FileNameSplit  ▪  FileNameDepth  ▪  ...

DirectoryQ — test whether a name corresponds to an existing directory

Directory Operations

CreateDirectory  ▪  RenameDirectory  ▪  CopyDirectory  ▪  DeleteDirectory

User File Directories

$UserDocumentsDirectory — default directory for saving notebooks

$WolframDocumentsDirectory — default directory for kernel file output

$HomeDirectory — user's home directory

$UserBaseDirectory — default base directory for user-specific add-on files

$Path — list of directories to search for files

System File Directories

$InitialDirectory — initial directory when the Wolfram System was started

$BaseDirectory — default base directory for systemwide add-on files

$InstallationDirectory — root of directories for Wolfram System installation files

$RootDirectory — file system root directory

$TemporaryDirectory — system temporary directory

FindFile — find a file by searching $Path, etc.