This standard enables: Software to predict the location of installed files and directories, and Users to predict the location of installed files and directories. We do this by: Specifying guiding principles for each area of the filesystem, Specifying the minimum files and directories required, Enumerating exceptions to the principles, and Enumerating specific cases where there has been historical conflict. The FHS document is used by: Independent software suppliers to create applications which are FHS compliant, and work with distributions which are FHS compliant, OS creators to provide systems which are FHS compliant, and Users to understand and maintain the FHS compliance of a system. The FHS document has a limited scope: Local placement of local files is a local issue, so FHS does not attempt to usurp system administrators. FHS addresses issues where file placements need to be coordinated between multiple parties such as local sites, distributions, applications, documentation, etc.

We recommend that you read a typeset version of this document rather than the plain text version. In the typeset version, the names of files and directories are displayed in a constant-width font. Components of filenames that vary are represented by a description of the contents enclosed in "<" and ">" characters, <thus>. Electronic mail addresses are also enclosed in "<" and ">" but are shown in the usual typeface. Optional components of filenames are enclosed in "[" and "]" characters and may be combined with the "<" and ">" convention. For example, if a filename is allowed to occur either with or without an extension, it might be represented by <filename>[.<extension>]. Variable substrings of directory names and filenames are indicated by "*". The sections of the text marked as Rationale are explanatory and are non-normative.