filename(3erl)						     Erlang Module Definition						    filename(3erl)

NAME

       filename - Filename Manipulation Functions

DESCRIPTION

       The  module  filename provides a number of useful functions for analyzing and manipulating file names. These functions are designed so that
       the Erlang code can work on many different platforms with different formats for file names. With file name is meant all strings that can be
       used  to denote a file. They can be short relative names like foo.erl , very long absolute name which include a drive designator and direc-
       tory names like D:usr/localinerl/lib	oolsfoo.erl , or any variations in between.

       In Windows, all functions return file names with forward slashes only, even if the arguments contain back slashes. Use join/1 to  normalize
       a file name by removing redundant directory separators.

       The  module  supports raw file names in the way that if a binary is present, or the file name cannot be interpreted according to the return
       value of file:native_name_encoding/0 , a raw file name will also be returned. For example filename:join/1 provided with	a  path  component
       being  a binary (and also not being possible to interpret under the current native file name encoding) will result in a raw file name being
       returned (the join operation will have been performed of course). For more information about raw file names, see the file module.

DATA TYPES

       name() = string() | atom() | DeepList | RawFilename
	 DeepList = [char() | atom() | DeepList]
	 RawFilename = binary()
	 If VM is in unicode filename mode, string() and char() are allowed to be > 255.
	 RawFilename is a filename not subject to Unicode translation, meaning that it
	 can contain characters not conforming to the Unicode encoding expected from the
	 filesystem (i.e. non-UTF-8 characters although the VM is started in Unicode
	 filename mode).

EXPORTS

       absname(Filename) -> string()

	      Types  Filename = name()

	      Converts a relative Filename and returns an absolute name. No attempt is made to create the shortest absolute name, because this can
	      give incorrect results on file systems which allow links.

	      Unix examples:

	      1> pwd().
	      "/usr/local"
	      2> filename:absname("foo").
	      "/usr/local/foo"
	      3> filename:absname("../x").
	      "/usr/local/../x"
	      4> filename:absname("/").
	      "/"

	      Windows examples:

	      1> pwd().
	      "D:/usr/local"
	      2> filename:absname("foo").
	      "D:/usr/local/foo"
	      3> filename:absname("../x").
	      "D:/usr/local/../x"
	      4> filename:absname("/").
	      "D:/"

       absname(Filename, Dir) -> string()

	      Types  Filename = name()
		     Dir = string()

	      This function works like absname/1 , except that the directory to which the file name should be made relative is given explicitly in
	      the Dir argument.

       absname_join(Dir, Filename) -> string()

	      Types  Dir = string()
		     Filename = name()

	      Joins an absolute directory with a relative filename. Similar to join/2 , but on platforms with tight restrictions on  raw  filename
	      length and no support for symbolic links (read: VxWorks), leading parent directory components in Filename are matched against trail-
	      ing directory components in Dir so they can be removed from the result - minimizing its length.

       basename(Filename) -> string()

	      Types  Filename = name()

	      Returns the last component of Filename , or Filename itself if it does not contain any directory separators.

	      5> filename:basename("foo").
	      "foo"
	      6> filename:basename("/usr/foo").
	      "foo"
	      7> filename:basename("/").
	      []

       basename(Filename, Ext) -> string()

	      Types  Filename = Ext = name()

	      Returns the last component of Filename with the extension Ext stripped. This function should be used to remove a specific  extension
	      which might, or might not, be there. Use rootname(basename(Filename)) to remove an extension that exists, but you are not sure which
	      one it is.

	      8> filename:basename("~/src/kalle.erl", ".erl").
	      "kalle"
	      9> filename:basename("~/src/kalle.beam", ".erl").
	      "kalle.beam"
	      10> filename:basename("~/src/kalle.old.erl", ".erl").
	      "kalle.old"
	      11> filename:rootname(filename:basename("~/src/kalle.erl")).
	      "kalle"
	      12> filename:rootname(filename:basename("~/src/kalle.beam")).
	      "kalle"

       dirname(Filename) -> string()

	      Types  Filename = name()

	      Returns the directory part of Filename .

	      13> filename:dirname("/usr/src/kalle.erl").
	      "/usr/src"
	      14> filename:dirname("kalle.erl").
	      "."

	      5> filename:dirname("\usr\src/kalle.erl").  % Windows
	      "/usr/src"

       extension(Filename) -> string()

	      Types  Filename = name()

	      Returns the file extension of Filename , including the period. Returns an empty string if there is no extension.

	      15> filename:extension("foo.erl").
	      ".erl"
	      16> filename:extension("beam.src/kalle").
	      []

       flatten(Filename) -> string()

	      Types  Filename = name()

	      Converts a possibly deep list filename consisting of characters and atoms into the corresponding flat string filename.

       join(Components) -> string()

	      Types  Components = [string()]

	      Joins a list of file name Components with directory separators. If one of the elements of Components includes an absolute path,  for
	      example "/xxx" , the preceding elements, if any, are removed from the result.

	      The result is "normalized":

		* Redundant directory separators are removed.

		* In Windows, all directory separators are forward slashes and the drive letter is in lower case.

	      17> filename:join(["/usr", "local", "bin"]).
	      "/usr/local/bin"
	      18> filename:join(["a/b///c/"]).
	      "a/b/c"

	      6> filename:join(["B:a\b///c/"]).  % Windows
	      "b:a/b/c"

       join(Name1, Name2) -> string()

	      Types  Name1 = Name2 = string()

	      Joins two file name components with directory separators. Equivalent to join([Name1, Name2]) .

       nativename(Path) -> string()

	      Types  Path = string()

	      Converts	Path  to a form accepted by the command shell and native applications on the current platform. On Windows, forward slashes
	      is converted to backward slashes. On all platforms, the name is normalized as done by join/1 .

	      19> filename:nativename("/usr/local/bin/").  % Unix
	      "/usr/local/bin"

	      7> filename:nativename("/usr/local/bin/").  % Windows
	      "\usr\local\bin"

       pathtype(Path) -> absolute | relative | volumerelative

	      Returns the type of path, one of absolute , relative , or volumerelative .

		absolute :
		  The path name refers to a specific file on a specific volume.

		  Unix example: /usr/local/bin

		  Windows example: D:/usr/local/bin

		relative :
		  The path name is relative to the current working directory on the current volume.

		  Example: foo/bar, ../src

		volumerelative :
		  The path name is relative to the current working directory on a specified volume, or it is a specific file on the current  work-
		  ing volume.

		  Windows example: D:bar.erl, /bar/foo.erl

       rootname(Filename) -> string()
       rootname(Filename, Ext) -> string()

	      Types  Filename = Ext = name()

	      Remove a filename extension. rootname/2 works as rootname/1 , except that the extension is removed only if it is Ext .

	      20> filename:rootname("/beam.src/kalle").
	      /beam.src/kalle"
	      21> filename:rootname("/beam.src/foo.erl").
	      "/beam.src/foo"
	      22> filename:rootname("/beam.src/foo.erl", ".erl").
	      "/beam.src/foo"
	      23> filename:rootname("/beam.src/foo.beam", ".erl").
	      "/beam.src/foo.beam"

       split(Filename) -> Components

	      Types  Filename = name()
		     Components = [string()]

	      Returns a list whose elements are the path components of Filename .

	      24> filename:split("/usr/local/bin").
	      ["/","usr","local","bin"]
	      25> filename:split("foo/bar").
	      ["foo","bar"]
	      26> filename:split("a:\msdev\include").
	      ["a:/","msdev","include"]

       find_src(Beam) -> {SourceFile, Options} | {error,{ErrorReason,Module}}
       find_src(Beam, Rules) -> {SourceFile, Options} | {error,{ErrorReason,Module}}

	      Types  Beam = Module | Filename
		     Module = atom()
		     Filename = string() | atom()
		     SourceFile = string()
		     Options = [Opt]
		     Opt = {i, string()} | {outdir, string()} | {d, atom()}
		     ErrorReason = non_existing | preloaded | interpreted

	      Finds  the  source  filename and compiler options for a module. The result can be fed to compile:file/2 in order to compile the file
	      again.

	      The Beam argument, which can be a string or an atom, specifies either the module name or the path to the source code, with or  with-
	      out the ".erl" extension. In either case, the module must be known by the code server, i.e. code:which(Module) must succeed.

	      Rules  describes	how the source directory can be found, when the object code directory is known. It is a list of tuples {BinSuffix,
	      SourceSuffix} and is interpreted as follows: If the end of the directory name where the object is located matches BinSuffix  ,  then
	      the source code directory has the same name, but with BinSuffix replaced by SourceSuffix . Rules defaults to:

	      [{"", ""}, {"ebin", "src"}, {"ebin", "esrc"}]

	      If  the  source file is found in the resulting directory, then the function returns that location together with Options . Otherwise,
	      the next rule is tried, and so on.

	      The function returns {SourceFile, Options} if it succeeds. SourceFile is the absolute path to the source	file  without  the  ".erl"
	      extension.  Options include the options which are necessary to recompile the file with compile:file/2 , but excludes options such as
	      report or verbose which do not change the way code is generated. The paths in the {outdir, Path} and {i, Path} options  are  guaran-
	      teed to be absolute.

Ericsson AB							   stdlib 1.17.3						    filename(3erl)