[Chapter 7] 7.2.27 File::Basename - Parse File Specifications
Author: Larry Wall, Tom Christiansen & Randal L. Schwartz
Date: 1999-07-02T02:02:22Z

#

| Chapter 7 The Standard Perl Library |

### 7.2.27 File::Basename - Parse File Specifications

    use File::Basename;

    ($name, $path, $suffix) = fileparse($fullname, @suffixlist)
    fileparse_set_fstype($os_string);  # $os_string specifies OS type
    $basename = basename($fullname, @suffixlist);
    $dirname = dirname($fullname);

    ($name, $path, $suffix) = fileparse("lib/File/Basename.pm", '\.pm');
    fileparse_set_fstype("VMS");
    $basename = basename("lib/File/Basename.pm", ".pm");
    $dirname = dirname("lib/File/Basename.pm");

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`", or "`MacOS`", 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 `/`, it assumes you are using UNIX emulation and applies the UNIX syntax rules instead for that function call only. If you haven't called `fileparse_set_fstype()`, the syntax is chosen by examining the `osname` entry from the Config package 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 be identical to the input file specification. Using UNIX file syntax:

      ($name, $path, $suffix) = fileparse('/virgil/aeneid/draft.book7',
                                                        '\.book\d+');

  would yield:

      $name   eq 'draft'
      $path   eq '/virgil/aeneid',
      $suffix eq '.book7'

  (Note that the suffix pattern is in single quotes. You'd have to double the backslashes if you used double quotes, since double quotes do backslash interpretation.) Similarly, using VMS syntax:

      ($name, $path, $suffix) = fileparse('Doc_Root:[Help]Rhetoric.Rnh', '\..*');

  would yield:

      $name   eq 'Rhetoric'
      $path   eq 'Doc_Root:[Help]'
      $suffix eq '.Rnh'

`basename`

  The `basename()` routine returns the first element of the list produced by calling `fileparse()` with the same arguments. It is provided for 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. When using UNIX or MS-DOS 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 . (dot).

7.2.26 Fcntl - Load the C fcntl.h Defines |  | 7.2.28 File::CheckTree - Run Many Tests on a Collection of Files