Clear contents of a locked file in windows

Need to clear the contents of a log file(s) which is(are) locked by a process already from command prompt. When I tried doing

echo "" > filename

I get a error saying, the file is locked by a process.

I couldn't even open the file in notepad, clear contents and save.

Currently I'm opening the file in notepad++ and quickly pressing CTRL + a,CTRL+x,CTRL+s :)

Is there a way to get this done from cmd? How is notepad++ able to handle edit and save while notepad is not able to?

3 Answers

You could use a program like Unlocker to release the lock:

I found the best solution for me is Powershell> Clear-Content filename.log

The Clear-Content cmdlet enables you to erase the contents of a file without deleting the file itself. For example, suppose you run this command:

Clear-Content c:\scripts\test.txt

When you execute that command the file Test.txt will still be in the folder C:\Scripts; there just won’t be any data of any kind in the file.

Wildcard characters can be used with Clear-Content. This command erases the contents of any file in C:\Scripts whose file name starts with the letter E:

Clear-Content c:\scripts\e*

You are not limited to erasing only text files. The following command deletes all the data in an Excel spreadsheet:

Clear-Content c:\scripts\test.xls

And this command erases the contents of the Word document C:\Scripts\Test.doc:

Clear-Content c:\scripts\test.doc

Locked files cannot be deleted, but they can be renamed. It could be that Notepad++ is using "safe saves" – creating a temporary file with the new contents, then quickly deleting the original (this step probably fails) and renaming temporary file to the original name.