use dos function to Rename files

Please help ... I am not a programming person. My coding skill is very basic.

I have more than 10,000 files that need to be renamed.

The old file name is oldName = 'C:\Users\aaa\bcd.docx.
the new file name is newFile = 'C:\Users\aaa\b - c - d.docx.

If I use movefile function, it would take me forever to complete the task. I am trying to use dos function but was unsuccessful. Here is my dos function:

dos(['rename "' oldName '" "' newName '"']);

and I got the following error: "The syntax of the command is incorrect."

Greatly appreciate the response ...

[Image Analyst]

movefile() should not take forever. Did you actually even try it?

[Star Strider]

I didn’t look at the movefile code, but since it has several options and is platform-independent, it may first have to determine the OS it’s using, and then branch to the correct section of its code for that OS and particular argument set with each call to it. A direct dos call may be more efficient for large numbers of files.

[Ken Atwell]

I'll second Image Analyst; I would at least try movefile before dismissing it as performance-inefficient.

For starters, dos will start a subprocess and run Windows' CMD command. For 10,000 files, that would take a very long time. movefile has the opportunity to do this without a subprocess -- though I must admit I don't know how movefile is implemented.

If you must absolutely go the dos route, the cost of starting 10,000 processes is likely to be punitive. Instead, create a batch (.BAT) file that contains the 10K rename commands, and then invoke dos once to run the batch file.

[per isakson]

Have a look at this function, cmd_rename. It's a wrapper for dos' rename It takes wildcards. However,

cmd_rename( 'h:\m\cssm\tmp', '???.docx', '? - ? - ?.docx' )

gave an unexpected result.

[Walter Roberson]

With regards to the implementation of movefile: up to R13, movefile and copyfile invoked DOS commands, including the DOS command attrib . The next version of MS Windows that came along moved attrib out of the default path, causing movefile and copyfile to break. Mathworks responded in R14 by switching to internal calls instead of invoking a process.

Answer 1

[Star Strider]

I haven’t used the dos function in a while, but you probably need to get rid of all but the enclosing quotes and definitely get rid of the square brackets, since they work as a concatenation operator and remove the intervening spaces.

This works:

fidt = fopen('abc.txt','wt');                                       % Create Demonstration File
fclose(fidt);                                                       % Close It
imhere1 = which('abc.txt')                                          % Verify File Exists
%
oldName = 'abc.txt';
newName = 'a-b-c.txt';
[status,cmdout] = dos(sprintf('rename %s %s', oldName, newName))    % Rename File
%
imhere2 = which('a-b-c.txt')                                        % Verify ‘rename’ Call Worked
%
imhere1 =
C:\Users\<USERNAME>\Documents\MATLAB\abc.txt
status =
     0.0000e+000
cmdout =
     ''
imhere2 =
C:\Users\<USERNAME>\Documents\MATLAB\a-b-c.txt

(I edited my user name out of the path, but there were no other changes.)

[Walter Roberson]

If you get rid of the "" then how will it deal with filenames that include spaces in them?

[Star Strider]

Excellent point, and one I searched the help on rename for without success. I couldn’t find anything in the documentation, so I experimented and discovered that putting double quotes inside the single quotes will accommodate spaces in the filename. Single quotes around the each string (in this code, using sprintf) are otherwise all that’s necessary:

fidt = fopen('abc.txt','wt');                                       % Create Demonstration File
fclose(fidt);                                                       % Close It
imhere1 = which('abc.txt')                                          % Verify File Exists
%
oldName = 'abc.txt';                                                % Without Spaces Within File Name, Only Single Quotes Are Necessary
%
newName = '"a - b - c.txt"';                                        % With Spaces Within The File Name, Put Double Quotes Inside Single Quotes
[status,cmdout] = dos(sprintf('rename %s %s', oldName, newName))    % Rename File
%
imhere2 = which('a - b - c.txt')                                    % Verify ‘rename’ Call Worked

Tested this. Success!

Anyway, the Question was how to do this in DOS, and this works.

[Walter Roberson]

Why not just always put the "" in the sprintf() ?

oldName = 'abc.txt';
newName = 'a - b - c.txt';
[status,cmdout] = dos(sprintf('rename "%s" "%s"', oldName, newName));

[Star Strider]

Thanks. I thought of that this morning, but was too tired last night to think to include it in the sprintf call.

Answer 2

[Jan]

Try the fast http://www.mathworks.com/matlabcentral/fileexchange/29569-filerename to move files, which is equivalent to a renaming.

R2011b, 800 Files a 100kb:

• movefile: 5.4 sec
• FileRename.mexw64: 0.9 sec
• java.io.File.renameTo: 1.0 sec

So Java is an alternative, if compiled Mex-code is a problem.

Answer 3

[NangHa]

Thank you all for great responses.

Dozen years ago, I renamed 500 video file, ~200MB each, using the movefile function. The task took me almost three days on the 386 processor machine. I am having a better PC now for the task. However, I am seeking for better solution than movefile since there are more than 10000 video files.

Again, thank you for great help ....

NangHa

[Star Strider]

Did you use my dos code? Did it do what you wanted it to?

[Jan]

Matlab 6.5 had a cruel implementation of MOVEFILE. The mentioned FEX submission was 1600 times faster. But Matlab improved the code and it was much faster in R2009a, such that the C-Mex was only 10 to 50 time faster. Since 2011b the speedup is only a factor of 5 to 6. I do not have a newer version yet, so I could not test the current relation.

[NangHa]

Star Strider, Thanks for your help. Your dos code is great. It took about 0.6 seconds to rename 45 files.

Again, greatly appreciate your help.

Also, I did try Jan Simon mex code and it is also very good.

Thank you all in response to my request ...

NangHa

[Star Strider]

My pleasure.

I am happy it worked for you.