python check if file is open by another process

542), How Intuit democratizes AI development across teams through reusability, We've added a "Necessary cookies only" option to the cookie consent popup. Context Managers help you work with files and manage them by closing them automatically when a task has been completed. The best suggestion I have for a Unix environment would be to look at the sources for the lsof command. Pythons dependency on external files is a crucial aspect, it's wise to pay heed to the base/source files before executing any code. Is the Dragonborn's Breath Weapon from Fizban's Treasury of Dragons an attack? You can work with this list in your program by assigning it to a variable or using it in a loop: We can also iterate over f directly (the file object) in a loop: Those are the main methods used to read file objects. Here you can see an example with FileNotFoundError: Tip: You can choose how to handle the situation by writing the appropriate code in the except block. The context manager does all the heavy work for us, it is readable, and concise. It can actually be done in an OS-independent way given a few assumptions, or as a combination of OS-dependent and OS-independent techniques. Consider this code: if not-in-use: use-the-file To close the file automatically after the task (regardless of whether an exception was raised or not in the try block) you can add the finally block. You could use that as the basis of your solution. In this case, .txt indicates that it's a text file. Filesystem to share disks between Linux and FreeBSD, FreeBSD-11 Mate desktop file browser unable to connect to https webdav url, How to check if process with pid X is the one you expect. This is exactly what I needed, and works as intended if you are doing a file operation, e.g scraping from the web then writing to a file and want to know when it's completed to either carry on operations or to display 'done' to the user. It is extremely important that we understand what the legacy application is doing, and what your python script is attempting to achieve. It has deep knowledge about which process have which files open. Not using the standard library, no. Tip: The file will be initially empty until you modify it. You can change your settings at any time, including withdrawing your consent, by using the toggles on the Cookie Policy, or by clicking on the manage consent button at the bottom of the screen. This is Windows specific, the question being about Excel then it makes sense, but not in every scenario this will be true. You could use with open("path") as file: so that it automatically closes, else if it's open in another process you can maybe try Instead on using os.remove() you may use the following workaround on Windows: You can use inotify to watch for activity in file system. The psutil is a system monitoring and system utilization module of python. Is there a way to check if the current file has been opened by another application? check if a file is open in Python python excel 187,716 Solution 1 I assume that you're writing to the file, then closing it (so the user can open it in Excel), and then, before re-opening it for append/write operations, you want to check that the file isn't still open in Excel? `os.rmdir` not working on empty directories? Is there a pythonic way to do this? This is posted as an answer, which it is not. So, we will iterate over all the running process and for each process whose name contains the given string,we will keep its info in a list i.e. Check if a file is not open nor being used by another process, The open-source game engine youve been waiting for: Godot (Ep. Each string represents a line to be added to the file. Torsion-free virtually free-by-cyclic groups. Thanks for contributing an answer to Stack Overflow! Leave dates as strings using read_excel function from pandas in python, How to merge several Excel sheets from different files into one file, Organizing data read from Excel to Pandas DataFrame. To set the pointer to the end of a file you can use seek(0, 2), this means set the pointer to position 0 relative to the end of the file (0 = absolute positioning, 1 = relative to the start of the file, 2 = relative to the end of the file). This question is about Excel and how it affects file locking. The legacy application is opening and closing the file every X minutes, but I do not want to assume that at t = t_0 + n*X + eps it already closed the file. This is the file now, after running the script: Tip: The new line might not be displayed in the file until f.close() runs. Has 90% of ice around Antarctica disappeared in less than a decade? The first step is to import the built-in function using the import os.path library. Connect and share knowledge within a single location that is structured and easy to search. This is another common exception when working with files. But, there has a condition is the second thread can not process the log file that's using to record the log. Note: There has another thread also will regularly to process these log files. In the above example, if you run this application and leave the target file untouched, the script will let you know that it has not been modified. "Appending" means adding something to the end of another thing. Here is how I did it: just write your log processing code in the except part and you are good to go. in code side, the pseudocode similars like below: So, how do i check is a file is already open or is used by other process? If check is true, and the process exits with a non-zero exit code, a CalledProcessError exception will be raised. The multiprocessing package offers both local and remote concurrency, effectively side-stepping the Global Interpreter Lock by using subprocesses instead of threads. You can use the type() function to confirm that the value returned by f.read() is a string: In this case, the entire file was printed because we did not specify a maximum number of bytes, but we can do this as well. It is supported in Python versions 2.6, 2.7, and 3.4+. @Ioannis Filippidis - If he hadn't given his answer, you wouldn't have been able to deliver your message. Find centralized, trusted content and collaborate around the technologies you use most. This looks like it may be a good solution on Unix. The technical storage or access is necessary for the legitimate purpose of storing preferences that are not requested by the subscriber or user. I only tested this on Windows. rev2023.3.1.43269. #, http://msdn2.microsoft.com/en-us/lib50(VS.60).aspx. Another alternative is to write it yourself in C or using ctypes - a lot of work. On similar grounds, the import os library statement can be used to check if the directory exists on your system. If you want to open and modify the file prefer to use the previous method. Python : How to delete a directory recursively using shutil.rmtree(), Debugging Multi-threading Applications with gdb debugger, Remote Debugging Tutorial using gdb Debugger, Process Identification in Linux Tutorial & Example. Could very old employee stock options still be accessible and viable? The '-d' function tests the existence of a directory and returns False for any file query in the test command. We further use this method to check if a particular file path refers to an already open descriptor or not. Let's see how you can delete files using Python. So it will return True. To provide the best experiences, we and our partners use technologies like cookies to store and/or access device information. If no options are specified, fstat reports on all open files in the system. os.path.isdir () method in Python is used to check whether the specified path is an existing directory or not. But, sorry i can not try to install the psutil package. Ackermann Function without Recursion or Stack. To measure the size of a large file in Python and not suffer any serious performance issues is not as difficult as it may seem, all you really need to do is make use of the file object's read/write pointer. Updated on July 30, 2020, Simple and reliable cloud website hosting, New! Every developer understands the need to create fall back codes, which can save a prorgram from failing in the case that a condition isn't met. For example, when you copy a large file in Windows, the created file will show its final size throughout the copying process, not its current size. This solution only can be used for Linux system. Browse other questions tagged. Inside Form1 I create a TCP Socket which is listening for connections to an IPEndPoint inside the network. If the file does not exist, Python will return False. Here is a generator that iterates over files in use for a specific PID: On Windows it is not quite so straightforward, the APIs are not published. Creating an MD5 hash of the entire file before and after a predetermined polling period can tell whether a file has been modified with a high amount of accuracy. For us to be able to work file objects, we need to have a way to "interact" with them in our program and that is exactly what methods do. You can simply write open(). Is there a way to check if a file is in use? In Linux there is only lsof. Why does awk -F work for most letters, but not for the letter "t"? Since the limitation of application framework. Using access () 3. attempting to find out what files are open in the legacy application, using the same techniques as ProcessExplorer (the equivalent of *nix's, you are even more vulnerable to race conditions than the OS-independent technique, it is highly unlikely that the legacy application uses locking, but if it is, locking is not a real option unless the legacy application can handle a locked file gracefully (by blocking, not by failing - and if your own application can guarantee that the file will not remain locked, blocking the legacy application for extender periods of time. I my application, i have below requests: They are slightly different, so let's see them in detail. This is basically telling us that a file object is an object that lets us work and interact with existing files in our Python program. Let's see some of the most common exceptions (runtime errors) that you might find when you work with files: According to the Python Documentation, this exception is: For example, if the file that you're trying to open doesn't exist in your current working directory: Let's break this error down this line by line: Tip: Python is very descriptive with the error messages, right? So, we will iterate over all the running process and for each process whose name contains the given string, we will keep it's info in a list i.e. How to print and connect to printer using flutter desktop via usb? The most accurate way to measure changes to a file is to directly compare the new version of the file to the old version. By clicking Accept all cookies, you agree Stack Exchange can store cookies on your device and disclose information in accordance with our Cookie Policy. However, if you're a beginner, there are always ways to learn Python. os.path.exists (path) Parameter. Function Syntax. Then it takes the return value of the code. Tip: The three letters .txt that follow the dot in names.txt is the "extension" of the file, or its type. How to open files for multiple operations. Check if File Exists using the pathlib Module # The pathlib module is available in Python 3.4 and above. Tip: A module is a Python file with related variables, functions, and classes. Tip: The write() method returns the number of characters written. Not the answer you're looking for? I wish to process all the files one, Mar 7 '07 Here are the Ubuntu sources for lsof. Python - How to check if a file is used by another application? "C:\Users\Wini Bhalla\Desktop\Python test file.txt", "C:\Users\Wini Bhalla\Desktop\testdirectory", try and except statement checks a command, Learning Python? To subscribe to this RSS feed, copy and paste this URL into your RSS reader. Drift correction for sensor readings using a high-pass filter. Launching the CI/CD and R Collectives and community editing features for How to skip files being used in another program? In her free time, she likes to paint, spend time with her family and travel to the mountains, whenever possible. Very nice solution. She has written content related to programming languages, cloud technology, AWS, Machine Learning, and much more. +1 Note that the fstat utility is specific to BSD and not related to the Linux stat/fstat system calls. Join Bytes to post your question to a community of 471,987 software developers and data experts. Not the answer you're looking for? For example, if you only need to read the content of a file, it can be dangerous to allow your program to modify it unexpectedly, which could potentially introduce bugs. How to work with context managers and why they are useful. Why should Python allow your program to do more than necessary? During her writing stints, she has been associated with digital marketing agencies and technical firms. Not finding what you were looking for or have an idea for a tutorial? def findProcessIdByName(processName): '''. The try and except statement checks a command and produces an output. To subscribe to this RSS feed, copy and paste this URL into your RSS reader. this is extremely intrusive and error prone. For checking the existence of a file(s), you can use any of the procedures listed above. Lets iterate over it and print them i.e. the try statement is being ignored on my end. This is an example of a context manager used to work with files: Tip: The body of the context manager has to be indented, just like we indent loops, functions, and classes. In contrast, readlines() returns a list with all the lines of the file as individual elements (strings). However, this method will not return any files existing in subfolders. That solves the problems brought up in the comments to his answer. Has Microsoft lowered its Windows 11 eligibility criteria? Here are multiple ways to check for a specific file or directory using Python. To subscribe to this RSS feed, copy and paste this URL into your RSS reader. By clicking Post Your Answer, you agree to our terms of service, privacy policy and cookie policy. Python : How to delete a directory recursively using, Get Column Index from Column Name in Pandas DataFrame. PTIJ Should we be afraid of Artificial Intelligence? rev2023.3.1.43269. Python is a relatively easy-to-use language, and it offers a lot of options to the end users. The fstat utility identifies open files. Here's an example. To check if process is running or not, lets iterate over all the running process using psutil.process_iter() and match the process name i.e. I realize it is probably OS dependent, so this may not really be python related right now. Pre-requisites: Ensure you have the latest Python version installed. The first parameter of the open() function is file, the absolute or relative path to the file that you are trying to work with. Does With(NoLock) help with query performance? #, Mar 7 '07 We usually use a relative path, which indicates where the file is located relative to the location of the script (Python file) that is calling the open() function. Findprocessidbyname ( processName ): & # x27 ; & # x27 ; & x27... Mar 7 '07 here are the Ubuntu sources for the letter `` t '' changes to a is. The most accurate way to check if file exists using the import os.path library there always. Monitoring and system utilization module of Python of a file ( s ), you would n't have been to. Content related to the Linux stat/fstat system calls and collaborate around the technologies use. Not related to programming languages, cloud technology, AWS, Machine Learning, and the exits! Filippidis - if he had n't given his answer that the fstat utility is specific BSD! It offers a lot of options to the end of another thing true and. Method returns the number of characters written context manager does all the files one, Mar 7 '07 here multiple... Regularly to process these log files subprocesses instead of threads looking for have! Dragons an attack is listening for connections to an already open descriptor or not, a CalledProcessError will., Mar 7 '07 here are the Ubuntu sources for lsof to already... Being used in another program of your solution import os.path library the lines the. ( NoLock ) help with query performance statement can be used for system... Easy to search Managers help you work with context Managers help you work with context help! Sensor readings using a high-pass filter given his answer, which it is supported in is! - if he had n't given his answer, which it is not statement is being ignored my!, Simple and reliable cloud website hosting, New number of characters written or is... Here is how i did it: just write your log processing code in the comments his... Very old employee stock options still be accessible and viable did it: just write your log processing code the. Is not os.path library process have which files open added to the end users be related! Disappeared in less than a decade 're a beginner, there are always ways to check if the file! Which process have which files open may be a good solution on Unix application i... Another application system monitoring and system utilization module of Python us, it is not for or have an for... Directory using Python the Linux stat/fstat system calls the end users remote,. And it offers a lot of work like it may be a good solution Unix! On July 30, 2020, Simple and reliable cloud website hosting, New monitoring and utilization! But not in every scenario this will be raised you can use any of procedures. Understand what the legacy application is doing, and concise executing any code using flutter desktop via usb case.txt. Letters.txt that follow the dot in names.txt is the `` extension '' of the procedures listed above it be. Using a high-pass filter a non-zero exit code, a CalledProcessError exception will be raised if file exists the. Options to the Linux stat/fstat system calls Managers help you work with files technical storage or is... To directly compare the New version of the file will be true monitoring system... To a community of 471,987 software developers and data experts is attempting to achieve true, and 3.4+:... File > ) Ubuntu sources for the lsof command open descriptor or not and system utilization of! To skip files being used in another program have been able to deliver your message another also... To write it yourself in C or using ctypes - a lot of work module of.. Is to import the built-in function using the import os library statement can used! Is an existing directory or not and classes this may not really be Python related right now stat/fstat... Any files existing in subfolders to post your question to a file ( s ), you would n't been... Of the procedures listed above procedures listed above the old version as an answer, which it is in! -F work for us, it 's wise to pay heed to the end users function the. Process exits with a non-zero exit code, a CalledProcessError exception will be true been associated digital... Experiences, we and our partners use technologies like cookies to store and/or device... Travel to the mountains, whenever possible specific to BSD and not related to the old version of written. External files is a crucial aspect, it 's a text file much more another! External files is a relatively easy-to-use language, and it offers a lot of work extremely important we! Is the second thread can not try to install the psutil package built-in function using the import os.path.! That follow the dot in names.txt is the Dragonborn 's Breath Weapon from Fizban 's of... Of Dragons an attack directory or not an answer, you would n't have been able deliver... In use - how to print and connect to printer using flutter desktop via usb the procedures above... I my application, i have for a Unix environment would be to look at the sources lsof! And how it affects file locking probably os dependent, so this may not really be Python related right.... My application, i have below requests: They are useful Python allow your program to do than! A file is used to check if the file to the file, or its type files used... Understand what the legacy application is doing, and the process exits with a non-zero exit code, a exception..., i have for a Unix environment would be to look at the sources for letter! `` t '' - how to check for a Unix environment would be look. Package offers both local and remote concurrency, effectively side-stepping the Global Interpreter Lock by using subprocesses instead threads... Weapon from Fizban 's Treasury of Dragons an attack write ( ) method returns the number of characters written open... Open and modify the file as individual elements ( strings ) less than a decade Managers help work. Also will regularly to process these log files 471,987 software developers and experts. Share knowledge within a single location that is structured and easy to.! Particular file path refers to an IPEndPoint inside the network statement checks a and! For a Unix environment would be to look at the sources for the lsof command spend with... The write ( ) method in Python 3.4 and above it 's wise to pay heed to end. Http: //msdn2.microsoft.com/en-us/lib50 ( VS.60 ).aspx the return value of the file does python check if file is open by another process exist, Python will False! Is listening for connections to an IPEndPoint inside the network, this method to check if a particular file refers! Be Python related right now ), you would n't have been able to deliver your message file )! The '-d ' function tests the existence of a file is in use hosting, New particular file refers! A few assumptions, or as a combination of OS-dependent and OS-independent techniques Breath Weapon from 's... Pay heed to the file prefer to use the previous method to do than... Less than a decade check is true, and what your Python script attempting., i have below requests: They are useful note that the utility!.Txt indicates that it 's wise to pay heed to the end of another thing experiences, we our... Of options to the mountains, whenever possible dependent, so this may not really be Python right... ( processName ): & # x27 ; by using subprocesses instead threads..., Python will return False provide the best suggestion i have for a specific or... The '-d ' function tests the existence of a file is used to check if file... Import os.path library i realize it is supported in Python 3.4 and above there a way to if. An output module # the pathlib module # the pathlib module is a Python file with related variables functions! Used by another application '07 here are the Ubuntu sources for the lsof command ice around Antarctica disappeared less! Condition is the `` extension '' of the file prefer to use the previous method names.txt is the extension... Technologies like cookies to store and/or access device information names.txt is the `` extension '' the... Alternative is to import the built-in function using the import os library statement can be used to if. There has another thread also will regularly to process these log files manage them closing!, which it is readable, and 3.4+ Get Column Index from Column Name in Pandas DataFrame, http //msdn2.microsoft.com/en-us/lib50... The multiprocessing package offers both local and remote concurrency, effectively side-stepping Global. N'T given his answer '' of the code and why They are slightly different, so let see! Query performance if the directory exists on your system: Ensure you the! Solves the problems brought up in the except part and you are good to go exists using pathlib! Or user characters written ( < file > ) wish to process all the files one, Mar 7 here... Allow your program to do more than necessary storage or access is necessary for the lsof command it the! Easy-To-Use language, and classes files being used in another program an idea for a specific file directory. Understand what the legacy application is doing, and 3.4+ her free time, has! Why should Python allow your program to do more than necessary 7 '07 are! File locking below requests: They are useful all open files in the test command letters that... Aws, Machine Learning, and classes, the import os.path library for or an... Time, she has written content related to the end of another thing and around... Or using ctypes - a lot of options to the end users most letters, but not for letter.

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