To make it clear, I am asking about finding out if a file was modified in general. True of False ? The modified time is not important. I cannot afford to open each file and compare its content with the original file unfortunately, since the original file is not accessible. PHP functions or linux command.
I would appreciate it.
Save the last modified time in the DB and get the latest modified time through the php function filemtime("filename") ,If they are same file is not modified and if not then it is modified and you can save the latest timestamp of the file in the DB for further uses.