These routines allow you to parse file specifications into
useful pieces using the syntax of different operating
systems.
fileparse_set_fstype
You select the syntax via the routine
fileparse_set_fstype().
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 fileparse(),
basename(), and 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 $^O
according to these rules.
fileparse
The fileparse() routine divides a file specification
into three parts: a leading path, a file name, and a
suffix. The path contains everything up to and
including the last directory separator in the input file
specification. The remainder of the input file
specification is then divided into name and suffix based
on the optional patterns you specify in @suffixlist.
Each element of this list is interpreted as a regular
expression, and is matched against the end of name. If
this succeeds, the matching portion of name is removed
and prepended to suffix. By proper use of @suffixlist,
you can remove file types or versions for examination.
You are guaranteed that if you concatenate path, name,
and suffix together in that order, the result will
denote the same file as the input file specification.
EXAMPLES
Using UNIX file syntax:
($base,$path,$type) = fileparse('/virgil/aeneid/draft.book7',
'\.book\d+');
would yield
$base eq 'draft'
$path eq '/virgil/aeneid/',
$type eq '.book7'
Similarly, using VMS syntax:
($name,$dir,$type) = fileparse('Doc_Root:[Help]Rhetoric.Rnh',
'\..*');
would yield
$name eq 'Rhetoric'
$dir eq 'Doc_Root:[Help]'
$type eq '.Rnh'
basename
The 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 basename(1).
dirname
The 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 .).