# Moving files with ruby **URL:** \ **Category:** Ruby\ **Created:** [August 24, 2006, 1:26am UTC](https://www.ruby-forum.com/t/moving-files-with-ruby/66216 "2006-08-24T01:26:47Z")\ **Posts on this page:** 6\ **Page:** 1
**Author:** ![darren\_kirby](https://www.ruby-forum.com/letter_avatar_proxy/v4/letter/d/ed8c4c/32.png) [@darren\_kirby](https://www.ruby-forum.com/u/darren_kirby)\ **Post date:** [August 24, 2006, 1:26am UTC](https://www.ruby-forum.com/t/moving-files-with-ruby/66216/1 "2006-08-24T01:26:47Z")
Hello all, A script I have written needs the ability to move files. I thought I would be clever and use File.rename(old, newdir + new) but this is giving me an error: `rename’: Invalid cross-device link. I gather this is because I am renaming the file to a different partition. So then I found FileUtils and used: require ‘fileutils’ include FileUtils mv( old, new) This is working but seems an overly verbose and convoluted way to move a file. I had a look at the fileutils.rb source and found this (for ‘mv’): # Moves file(s) +src+ to +dest+. If +file+ and +dest+ exist on the different # disk partition, the file is copied instead So I guess my real question is: is there a technical reason or some arbitrary reason there is no File.move() method that can handle this transparently? I would think it would be quite useful… Any insight is appreciated, -d ---
**Author:** ![darren\_kirby](https://www.ruby-forum.com/letter_avatar_proxy/v4/letter/d/ed8c4c/32.png) [@darren\_kirby](https://www.ruby-forum.com/u/darren_kirby)\ **Post date:** [August 24, 2006, 1:46am UTC](https://www.ruby-forum.com/t/moving-files-with-ruby/66216/2 "2006-08-24T01:46:49Z")
darren kirby wrote: > Hello all, > > A script I have written needs the ability to move files. I thought I would > be clever and use File.rename(old, newdir + new) but this is giving me an > error: `rename’: Invalid cross-device link. I gather this is because I am > renaming the file to a different partition. No, it is because you are trying to use “rename” to physically move a file, and the system is objecting to this misconception. File.rename can only rename files, it cannot move them. It works only on one storage device/volume/whatever. > So then I found FileUtils and used: > require ‘fileutils’ > include FileUtils > mv( old, new) > > This is working but seems an overly verbose and convoluted way to move a > file. Umm, compared to what? It moves the file using a method named “mv”, just like the Linux/Unix command of the same name. > I had a look at the fileutils.rb source and found this (for ‘mv’): > > # Moves file(s) +src+ to +dest+. If +file+ and +dest+ exist on the > > # different disk partition, the file is copied instead That is what “mv” does. If the new and old filenames and paths allow the file to remain on the same device, a simple rename is carried out. If not, the file is copied to the destination and deleted from the source. > So I guess my real question is: is there a technical reason or some > arbitrary reason there is no File.move() method that can handle this > transparently? I would think it would be quite useful… It might be because not all operating systems on which Ruby can be installed know the “mv” operation as described above. Just a guess. ---
**Author:** ![darren\_kirby](https://www.ruby-forum.com/letter_avatar_proxy/v4/letter/d/ed8c4c/32.png) [@darren\_kirby](https://www.ruby-forum.com/u/darren_kirby)\ **Post date:** [August 24, 2006, 2:10am UTC](https://www.ruby-forum.com/t/moving-files-with-ruby/66216/3 "2006-08-24T02:10:50Z")
quoth the Paul L.: > rename files, it cannot move them. It works only on one storage > device/volume/whatever. Well, I think that’s pretty much what I said. If you ‘rename’ a file from /somepath/somefile.txt to /someotherpath/somefile.txt within the same partition you have effectively ‘moved’ it haven’t you… > > So then I found FileUtils and used: > > require ‘fileutils’ > > include FileUtils > > mv( old, new) > > > > This is working but seems an overly verbose and convoluted way to move a > > file. > > Umm, compared to what? It moves the file using a method named “mv”, just > like the Linux/Unix command of the same name. I am typically very impressed with how much you can do with a little amount of code in Ruby. For instance, I only had to add one line to add some recursive directory handling in my script: From: files += Dir.glob("_.#{t}") To: files += Dir.glob("\*\*/_.#{t}") Whereas to move a file, a fairly basic operation, I need four lines of code: require ‘fileutils’ include FileUtils cp(old, new ) rm (old) I have to change “mv” to “cp” and add the “rm” because the old file is not automatically removed… > > I had a look at the fileutils.rb source and found this (for ‘mv’): > > > > # Moves file(s) +src+ to +dest+. If +file+ and +dest+ exist on the > > > > # different disk partition, the file is copied instead > > That is what “mv” does. If the new and old filenames and paths allow the > file to remain on the same device, a simple rename is carried out. If not, > the file is copied to the destination and deleted from the source. Right, I’ve got that… > > So I guess my real question is: is there a technical reason or some > > arbitrary reason there is no File.move() method that can handle this > > transparently? I would think it would be quite useful… > > It might be because not all operating systems on which Ruby can be > installed know the “mv” operation as described above. Just a guess. I am just wondering because there are (AFAIK) other methods that handle the operation transparently even though the underlying OS does it differently. Not trying to troll, I am just curious… -d ---
**Author:** ![darren\_kirby](https://www.ruby-forum.com/letter_avatar_proxy/v4/letter/d/ed8c4c/32.png) [@darren\_kirby](https://www.ruby-forum.com/u/darren_kirby)\ **Post date:** [August 24, 2006, 5:31am UTC](https://www.ruby-forum.com/t/moving-files-with-ruby/66216/4 "2006-08-24T05:31:05Z")
Marc H. wrote: > well > system(“mv #{file}”) > is also possible ,) But not generic for cross-platform re-use. ---
**Author:** ![darren\_kirby](https://www.ruby-forum.com/letter_avatar_proxy/v4/letter/d/ed8c4c/32.png) [@darren\_kirby](https://www.ruby-forum.com/u/darren_kirby)\ **Post date:** [August 24, 2006, 4:13am UTC](https://www.ruby-forum.com/t/moving-files-with-ruby/66216/5 "2006-08-24T04:13:12Z")
well system(“mv #{file}”) is also possible ,) include FileUtils isnt needed so that should reduce your LOC by -1 Doesnt FileUtils have mv(src, dest, options) ? Anyway, why not this? [http://www.ruby-doc.org/core/classes/FileUtils.html#M002613](http://www.ruby-doc.org/core/classes/FileUtils.html#M002613) ---
**Author:** ![darren\_kirby](https://www.ruby-forum.com/letter_avatar_proxy/v4/letter/d/ed8c4c/32.png) [@darren\_kirby](https://www.ruby-forum.com/u/darren_kirby)\ **Post date:** [August 24, 2006, 6:01am UTC](https://www.ruby-forum.com/t/moving-files-with-ruby/66216/6 "2006-08-24T06:01:08Z")
quoth the Marc H.: > well > system(“mv #{file}”) > is also possible ,) I may be wrong, but I always had the impression that using a system command to do something available within the language is considered a kludge. > include FileUtils isnt needed so that should reduce your > LOC by -1 When I comment the line out I get: undefined method `cp’ for main:Object (NoMethodError) > Doesnt FileUtils have > mv(src, dest, options) > ? Yes, it does. But the thing is that if you are moving the file across partitions it will only copy and not delete the original file. I will not know if we are moving cross-partition, so I have to use cp and rm… > Anyway, why not this? > > [http://www.ruby-doc.org/core/classes/FileUtils.html#M002613](http://www.ruby-doc.org/core/classes/FileUtils.html#M002613) From the link: “If file and dest exist on the different disk partition, the file is copied instead.” -d