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Renaming Files Throughout a Directory Tree

Problem

You need to rename files throughout an entire directory tree, for example, you want to change extension of every file with a particular extension to something else.

Solution

A PLT-specific solution: 

(require (lib "13.ss" "srfi"))

(define (rename-tree basedir oldext newext)
  (let ((extlen (string-length oldext))
        (file-list (find-files 
                    (lambda (x) 
                      (and (equal? (filename-extension x) "xsd")
                           (not (directory-exists? x)))) 
                    basedir)))
    (for-each (lambda (file-name) 
                (let ((newname (string-append (string-drop-right file-name extlen) newext)))
                (when (file-exists? newname) (delete-file newname))
                (rename-file-or-directory file-name 
                                          newname))
              file-list))))

Discussion

I wrote this solution to use for-each because the rename operation is a side effect. You could also use fold-files, which isn't quite as good a fit because it accumulates a result, but the definition is a bit more concise. It also doesn't explicitly build up a list of files to modify first, which can amount to a lot of memory on a big directory tree. 

(define (rename-tree basedir oldext newext)
  (let ((extlen (string-length oldext)))
    (fold-files (lambda (f t d) 
                  (when (and (eq? t 'file) 
                             (equal? (filename-extension f) "xsd"))
                    (let ((newname (string-append (string-drop-right f extlen) newext)))
                      (when (file-exists? newname) (delete-file newname))
                      (rename-file-or-directory 
                       f 
                       newname)))) 
                (void) basedir)))

For a really correct

Comments about this recipe

Contributors

-- GordonWeakliem - 13 Aug 2004

CookbookForm
TopicType: Recipe
ParentTopic: FileRecipes
TopicOrder: 999

 
 
Current Rev: r1.2 - 07 Sep 2004 - 21:53 GMT - GordonWeakliem, Revision History:Diffs | r1.2 | > | r1.1
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Other than such compilations, this material can be redistributed and/or modified under the terms of the GNU Lesser General Public License (LGPL), version 2.1, as published by the Free Software Foundation.
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