I can't seem to find any information on what happens if you read/search a file using a Windows Batch Script when the file still needs to be editable at the same time (eg an application log file bring written to in real time).
Does the batch file lock the file you are reading/searching?
Does it read the file contents from the particular datetime you accessed it only ignoring any subsequent edits. In particular, I'm interested in the answer for using for /f or findstr or find.
Thanks
Related
I started using robocopy with /Z switch and log option. I started copying 109+ GB file , it is more than two days and still getting copied. Since I ran copy with log option (/LOG+) , I cannot see percentage of completion. Is it safe to open log , while copy is in progress to see percentage of completion. Do not want file copy interrupted by opening log file. Is it safe to copy the log file to a different location and open it. Can some one clarify me on this?
Whether or not it is possible to open it, depends on the program you're using for that matter: programs like Notepad and Notepad++ are able to open a file, while another process is still writing to it, MS-Word is not able to do that. The largest difference between Notepad and Notepad++ for this matter is that Notepad can't refresh the file (or reload from disk, as it is called in Notepad++).
In case you have a Linux subsystem on your PC, you might use the tail -f feature, which is written especially for this purpose.
I'm looking for a method which would allow me to automatically open a modified file in windows. In other words, something running in the background which detects changes in a given set of files; such that when one is detected, the file is opened. I attempted writing a batch file which saves the last modified date and time to a text file and repeatedly checks that. I think this method works, but I didn't know if there's a better way out there.
My motivation is that I'm scp'ing files regularly from a linux machine to windows, and it would be neat if they just opened automatically on my windows machine after updating locally.
I'm looking for a editor in windows that constantly saves file.
In linux I do
cat>somefile
and then just start typing. somefile gets filled up as I type.
Is there editor or similar thing in WIndows? Preferably a non-dos tool?
I use WebStorm from JetBrains, which saves constantly and unobtrusively.
I really love it. I use it as a text editor and for my web development.
http://www.jetbrains.com/webstorm/
(and no I don't work there).
Its possible to install some unix features to windows.
Have a look at this CoreUtils
The shareware text editor UltraEdit by default works with using a temporary file which means create a copy of the file to edit in directory %TEMP% and copy this temporary file on save back to original file. The usage of a temporary file makes it possible to use Undo and Redo.
But it is possible at Advanced - Configuration - File Handling - Temporary Files to disable the usage of a temporary file for all files or just for large files depending on a threshold value in KB. All edits made on a file opened without usage of a temporary file are permanent which means immediately done on storage media.
Another feature of UltraEdit is automatic save in regular intervals which can be configured at Advanced - Configuration - File Handling - Save with or without making a backup on every save and even supporting version backups which means backups with an incrementing number on every save.
Last but not least on usage of a temporary file for editing a file as by default UltraEdit can recover last edits if UltraEdit crashes (uedit32.exe process killed with Windows task manager), or Windows crashes, or a sudden power loss occurs. The temporary file is updated quite often in the background by UltraEdit and therefore the restore on next start after an unexpected end of the editing session often restores nearly all edits made last on a file. The recovery feature includes also new files not being saved ever as file with a file name.
It would be interesting to know for offering a perhaps better solution why you want that any edit is immediately written to the file. In general this is the opposite of what users want on editing a text file and is not good on some storage medias like SSD hard disks.
I have 2 applications running in parallel, both doing the following:
check for file not containing "processed"
process the file and then rename it to filename+processed
for every file, only one application shall use it (on a first come first served basis)
I get the files and I also lock them so the other application cannot process it. But when it comes to renaming the file I get a problem. To rename the file, wanted to use the File.renameTo function. However, for that to work, I have to release the lock on the file. But when I release the lock another process may try to use the file. Exactly that should not happen.
Is there any way to prevent the application B from using the file between application A releasing the lock and finishing renaming the file?
EDIT
Some more information:
File creation if the file doesn't exist has to be prevented.
The file will be processed RandomAccessFile (with read and write permission; this creates a new file if it doesn't exist).
Note: On linux, one can rename a file that is locked, so this problem doesn't occur there. However, on Windows a locked file cannot be renamed; I have to release the lock, then rename it. But the time, during which the lock is released creates enables other applications to see that the file is available and then they will try to use it.
Windows applications can do this using the SetFileInformationByHandle function, which allows you to rename the file using the handle you already have open. You probably can't do this natively from Java.
However, a more straightforward solution would be to rename the file (to filename+processing, for example) before you start processing it. Whichever process successfully renames the file in this way is the one responsible for processing it and eventually renaming it to filename+processed.
I'm currently in working on a script to create a custom backup script, the only piece I'm missing is a file monitor. I need some form of a script that will monitor a folder for file changes, and then run a command with the file that's changed.
So, for example, if the file changes, it'll execute "c:/syncbatch.bat %Location_Of_File%"
In VBScript, you can monitor a folder for file changes by subscribing to the WMI __InstanceModificationEvent event. These articles contain sample code that you can learn from and adapt to your specific needs:
WMI and File System Monitoring
How Can I Monitor for Different Types of Events With Just One Script?
Calling WMI is fairly cryptic and it causes the WMI service to start running which can contribute to bloat since its fairly large and you really can't cancel the file change notifications you've requested from it without rebooting. Some people experimenting with remote printing from a Dropbox folder found that a simple VBScript program that ran an endless loop with a 10 second WScript.Sleep call in the loop used far less resource. Of course to stop it you have to task kill that script or program into it some exit trigger it can find like a specifically named empty file in the watch folder, but that is still easier to do than messing with WMI.
The Folder Spy http://venussoftcorporation.blogspot.com/2010/05/thefolderspy.html
is a free lightweight DOT.NET based file/folder watching GUI application I'ved used before to run scripts based on file changes. It looks like the new version can pass the event filename to the launched command. The old version I had didn't yet support file event info so when launched, my script had to instance a File System Object and scan the watched folder to locate the new files based on criteria like datestamps and sizes.
This newer version appears to let you pass the file name to the script if you say myscript.vbs "*f" on the optional script call entry. Quotes can be important when passing file paths that have spaces in folder names. Just remember if you are watching change events you will get a lot of them as a file grows or is edited, usually you just want notification of file adds or deletes.
Another trick your script can do is put the file size in a variable, sleep for a few seconds, and check the file again to see if its changed. if it hasn't changed in a few seconds you can usually assume whatever created it is done writing it to disk. if it keeps changing just loop until its stable.