perl-doc 5.26.1-6 / usr / share / perl / 5.26.1 / File / Basename.pod

=head1 NAME

File::Basename - Parse file paths into directory, filename and suffix.

=head1 SYNOPSIS

    use File::Basename;

    ($name,$path,$suffix) = fileparse($fullname,@suffixlist);
    $name = fileparse($fullname,@suffixlist);

    $basename = basename($fullname,@suffixlist);
    $dirname  = dirname($fullname);

=head1 DESCRIPTION

These routines allow you to parse file paths into their directory, filename
and suffix.

B<NOTE>: C<dirname()> and C<basename()> emulate the behaviours, and
quirks, of the shell and C functions of the same name.  See each
function's documentation for details.  If your concern is just parsing
paths it is safer to use L<File::Spec>'s C<splitpath()> and
C<splitdir()> methods.

It is guaranteed that

    # Where $path_separator is / for Unix, \ for Windows, etc...
    dirname($path) . $path_separator . basename($path);

is equivalent to the original path for all systems but VMS.

=over 4

=item C<fileparse>
X<fileparse>

    my($filename, $dirs, $suffix) = fileparse($path);
    my($filename, $dirs, $suffix) = fileparse($path, @suffixes);
    my $filename                  = fileparse($path, @suffixes);

The C<fileparse()> routine divides a file path into its $dirs, $filename
and (optionally) the filename $suffix.

$dirs contains everything up to and including the last
directory separator in the $path including the volume (if applicable).
The remainder of the $path is the $filename.

     # On Unix returns ("baz", "/foo/bar/", "")
     fileparse("/foo/bar/baz");

     # On Windows returns ("baz", 'C:\foo\bar\', "")
     fileparse('C:\foo\bar\baz');

     # On Unix returns ("", "/foo/bar/baz/", "")
     fileparse("/foo/bar/baz/");

If @suffixes are given each element is a pattern (either a string or a
C<qr//>) matched against the end of the $filename.  The matching
portion is removed and becomes the $suffix.

     # On Unix returns ("baz", "/foo/bar/", ".txt")
     fileparse("/foo/bar/baz.txt", qr/\.[^.]*/);

If type is non-Unix (see L</fileparse_set_fstype>) then the pattern
matching for suffix removal is performed case-insensitively, since
those systems are not case-sensitive when opening existing files.

You are guaranteed that C<$dirs . $filename . $suffix> will
denote the same location as the original $path.

=item C<basename>
X<basename> X<filename>

    my $filename = basename($path);
    my $filename = basename($path, @suffixes);

This function is provided for compatibility with the Unix shell command
C<basename(1)>.  It does B<NOT> always return the file name portion of a
path as you might expect.  To be safe, if you want the file name portion of
a path use C<fileparse()>.

C<basename()> returns the last level of a filepath even if the last
level is clearly directory.  In effect, it is acting like C<pop()> for
paths.  This differs from C<fileparse()>'s behaviour.

    # Both return "bar"
    basename("/foo/bar");
    basename("/foo/bar/");

@suffixes work as in C<fileparse()> except all regex metacharacters are
quoted.

    # These two function calls are equivalent.
    my $filename = basename("/foo/bar/baz.txt",  ".txt");
    my $filename = fileparse("/foo/bar/baz.txt", qr/\Q.txt\E/);

Also note that in order to be compatible with the shell command,
C<basename()> does not strip off a suffix if it is identical to the
remaining characters in the filename.

=item C<dirname>
X<dirname>

This function is provided for compatibility with the Unix shell
command C<dirname(1)> and has inherited some of its quirks.  In spite of
its name it does B<NOT> always return the directory name as you might
expect.  To be safe, if you want the directory name of a path use
C<fileparse()>.

Only on VMS (where there is no ambiguity between the file and directory
portions of a path) and AmigaOS (possibly due to an implementation quirk in
this module) does C<dirname()> work like C<fileparse($path)>, returning just the
$dirs.

    # On VMS and AmigaOS
    my $dirs = dirname($path);

When using Unix or MSDOS syntax this emulates the C<dirname(1)> shell function
which is subtly different from how C<fileparse()> works.  It returns all but
the last level of a file path even if the last level is clearly a directory.
In effect, it is not returning the directory portion but simply the path one
level up acting like C<chop()> for file paths.

Also unlike C<fileparse()>, C<dirname()> does not include a trailing slash on
its returned path.

    # returns /foo/bar.  fileparse() would return /foo/bar/
    dirname("/foo/bar/baz");

    # also returns /foo/bar despite the fact that baz is clearly a 
    # directory.  fileparse() would return /foo/bar/baz/
    dirname("/foo/bar/baz/");

    # returns '.'.  fileparse() would return 'foo/'
    dirname("foo/");

Under VMS, if there is no directory information in the $path, then the
current default device and directory is used.

=item C<fileparse_set_fstype>
X<filesystem>

  my $type = fileparse_set_fstype();
  my $previous_type = fileparse_set_fstype($type);

Normally File::Basename will assume a file path type native to your current
operating system (ie. /foo/bar style on Unix, \foo\bar on Windows, etc...).
With this function you can override that assumption.

Valid $types are "MacOS", "VMS", "AmigaOS", "OS2", "RISCOS",
"MSWin32", "DOS" (also "MSDOS" for backwards bug compatibility),
"Epoc" and "Unix" (all case-insensitive).  If an unrecognized $type is
given "Unix" will be assumed.

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.

=back

=head1 SEE ALSO

L<dirname(1)>, L<basename(1)>, L<File::Spec>
=cut