Case-sensitive file move

Is it possible to rename a file if the only difference between the old and new names is the case? A command such as

movefile('test.txt','Test.txt')

returns the error

Cannot copy or move a file or directory onto itself.

I'm making a GUI with the option to rename files, and while being able to do case-sensitive moves like that is not essential, it would certainly be nice.

Answer 1

[Walter Roberson]

movefile() on the same filesystem does not make a copy of the original file. You can see this by examining the ownerships and permissions and timestamps: they stay the same as long as the filesystem stays the same. (Whether they stay the same when moved to a different filesystem is dependent upon the operating system and file systems involved.)

But that is a detail. The difficulty is that most filesystems for MS Windows either are always case-insensitive or else are typically configured to be case-insensitive. For those filesystems MS Windows detects that the filename is not changing as far as the filesystem is concerned and it refuses the movefile()

The work-around is to movefile() to a name that is not in use, and then movefile() to the new name.

src = 'test.txt';
dest = 'Test.txt';

if isempty(src) || isempty(dest) || ~ischar(src) || ~ischar(dest)
  error('source or destination are invalid');
end

if strcmp(src, dest)
   warning('source and destination are the same, nothing done');
elseif ispc() && strcmpi(src, dest)
   %MS Windows is usually case-insensitive so we need a work-around
   %do not assume that the source is the current directory
   srcdir = fileparts(src);
   if isempty(srcdir); srcdir = pwd(); end  %in case no directory spec was included
   tname = tempname(srcdir);
   movefile(src, tname);
   movefile(tname, dest);
else
   movefile(src, dest);
 end

The above code is not fool-proof. In particular it does not check for the possibility that the src and dest refer to the same file through different paths. For example './test.txt' would be considered different than 'Test.txt' in this code even though they refer to the same file. The code also does not check whether the src is a directory, which is invalid for movefile(). (A destination which is a directory is valid for movefile())

[Hans Elzinga]

Thanks! I hadn't thought of performing the move to a temporary name automatically, and wasn't aware of the tempname function. The GUI can only rename files within a single, known folder (any entered file name with a slash or backslash gives a custom error), so attempts to move folders and uses of "./" aliases are not an issue.

Answer 2

[Vaibhav Awale]

Hi,

The command;

>> movefile('test.txt','Test.txt')

makes a copy of the original file and then removes the original file. Now both files are located in the same folder and Windows systems are not case sensitive with respect to file names. Hence MATLAB throws an error saying "Cannot copy or move a file or directory onto itself."

Regards,

Vaibhav Awale