Detect New File in a Directory
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Hi All,
Last time when I google this question, I actually found a function that does what I need, but I couldn't find it this time.
Basically what I need is to monitor a directory for any new files. If there are new files, I will read the files in and continue to monitor for new files.
Any help will be greatly appreciated!
Thank you,
Lynniz
댓글 수: 2
Walter Roberson
2011년 10월 13일
The mechanisms for doing this are operating-system specific. Please indicate which OS you are using.
채택된 답변
Honglei Chen
2011년 10월 13일
Hi lynniz,
You can use dir to list all the files under a certain directory, cache it and constantly query the folder and use setdiff to see whether a new file showed up. The following example shows a brief example. Note that I'm assuming everything underneath the directory is a regular file. If you have subdirectories, you can filter them out using the isdir field in the result of dir.
dir_content = dir;
filenames = {dir_content.name};
current_files = filenames;
while true
dir_content = dir;
filenames = {dir_content.name};
new_files = setdiff(filenames,current_files);
if ~isempty(new_files)
% deal with the new files
current_files = filenames;
else
fprintf('no new files\n')
end
end
Of course you may want to define an exit flag to get you out of the loop easily.
HTH
댓글 수: 3
Fangjun Jiang
2011년 10월 13일
What if file name keeps the same but it is newly updated? You might need to check the time stamp of the file, compare it to the last time that the checking is done, to see if it is "new".
추가 답변 (2개)
Dimitrios Patikas
2022년 8월 27일
편집: Dimitrios Patikas
2022년 8월 27일
To avoid looping over and over again, you may use a timer function and keep it working on the background unless younstom the timer. An example to get always the newest file:
t = timer;
t.TimerFcn = @timerFunc;
t.Period = 0.6; % how often you want to check
t.ExecutionMode = 'fixedRate';
t.start % use t.stop to stop the timer
function timerFunc(~,~)
persistent CurrentNewest
Path = 'A/path/you/want/to/keep/track';
CurrentNewest = 'NewestFilename.new'
ListFiles = dir(Path);
ListFiles = ListFiles(~[ListFiles.isdir]);
[~, idx] = sort([ListFiles.datenum]);
newest = ListFiles(idx(end));
if ~strcmp(newest.name, CurrentNewest)
disp(['The newest file is now: ', newest.name])
CurrentNewest = newest.name;
end
end
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