See the current Perl documentation for File::Basename.
Here is our local, out-dated (pre-5.6) version:
fileparse - split a pathname into pieces
basename - extract just the filename from a path
dirname - extract just the directory from a path
($name,$path,$suffix) = fileparse($fullname,@suffixlist) fileparse_set_fstype($os_string); $basename = basename($fullname,@suffixlist); $dirname = dirname($full
These routines allow you to parse file specifications into useful pieces using the syntax of different operating systems.
You select the syntax via the routine
If the argument passed to it contains one of the substrings ``VMS'', ``MSDOS'', ``MacOS'', ``AmigaOS'' or ``MSWin32'', the file specification syntax of that operating system is used in future calls to
dirname().If it contains none of these substrings, UNIX syntax is used. This pattern matching is case-insensitive. If you've selected VMS syntax, and the file specification you pass to one of these routines contains a ``/'', they assume you are using UNIX emulation and apply the UNIX syntax rules instead, for that function call only.
If the argument passed to it contains one of the substrings ``VMS'', ``MSDOS'', ``MacOS'', ``AmigaOS'', ``os2'', ``MSWin32'' or ``RISCOS'', then the pattern matching for suffix removal is performed without regard for case, since those systems are not case-sensitive when opening existing files (though some of them preserve case on file creation).
If you haven't called
fileparse_set_fstype(),the syntax is chosen by examining the builtin variable
$^Oaccording to these rules.
fileparse()routine divides a file specification into three parts: a leading path, a file name, and a suffix. The path contains everything up to and including the last directory separator in the input file specification. The remainder of the input file specification is then divided into name and suffix based on the optional patterns you specify in
@suffixlist. Each element of this list is interpreted as a regular expression, and is matched against the end of name. If this succeeds, the matching portion of name is removed and prepended to suffix. By proper use of
@suffixlist, you can remove file types or versions for examination.
You are guaranteed that if you concatenate path, name, and suffix together in that order, the result will denote the same file as the input file specification.
Using UNIX file syntax:
($base,$path,$type) = fileparse('/virgil/aeneid/draft.book7', '\.book\d+');
$base eq 'draft' $path eq '/virgil/aeneid/', $type eq '.book7'
Similarly, using VMS syntax:
($name,$dir,$type) = fileparse('Doc_Root:[Help]Rhetoric.Rnh', '\..*');
$name eq 'Rhetoric' $dir eq 'Doc_Root:[Help]' $type eq '.Rnh'
basename()routine returns the first element of the list produced by calling
fileparse()with the same arguments, except that it always quotes metacharacters in the given suffixes. It is provided for programmer compatibility with the UNIX shell command
dirname()routine returns the directory portion of the input file specification. When using VMS or MacOS syntax, this is identical to the second element of the list produced by calling
fileparse()with the same input file specification. (Under VMS, if there is no directory information in the input file specification, then the current default device and directory are returned.) When using UNIX or MSDOS syntax, the return value conforms to the behavior of the UNIX shell command
dirname(1).This is usually the same as the behavior of
fileparse(),but differs in some cases. For example, for the input file specification lib/,
fileparse()considers the directory name to be lib/, while
dirname()considers the directory name to be .).