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Programming Perl

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The Standard Perl Library
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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).


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7.2.26 Fcntl - Load the C fcntl.h DefinesBook Index7.2.28 File::CheckTree - Run Many Tests on a Collection of Files