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How to give read and write permission to a file in python

How to give read and write permission to a file in python

By using our site, you acknowledge that you have read and understand our Cookie PolicyPrivacy Policyand our Terms of Service. Ask Ubuntu is a question and answer site for Ubuntu users and developers. It only takes a minute to sign up. I m using Ubuntu I want to transfer media files to and from them freely through programs. Assuming you have both partitions mounted with the names part1 and part2, you will be the only one using them and you want total free control over them, I would do this:.

The first 7 Starting from the Left is for the owner, the 2nd is for the group where the owner resides. The last 7 is for other groups. Basically like this you can copy anything you want in the partitions and if you ever need to take the HDD out and connect it to another computer with Ubuntu you will not have any problems with permissions. At least in my case it saves me time because I tend to have 1 or 2 hard drives that hold movies, music and similar stuff and I move them around from PC to PC.

Just to add, if you do not know where the partitions are mounted, you can always open Disk Utility and in the information about the hard drive it will tell you where it is mounted. Instead of changing all file permissions, like Luis Alvarado suggested, it would be better to change the file owner - thus keeping the executable bit on any binary and script files that previously had it. You should be able to mount the partition from nautilus Ubuntu's default file manager.

If you look at the top left hand side of the window, you should be able to see all of the partitions you have on your drive. Just click on one to mount it. The line that you would add should be something like:. To do this, follow these steps:. I will simply use "MyMount1" and "MyMount2" for an example. Also, I will use "mylogin" to represent your login name and group; change this to your login account name.

To get these, run sudo blkid from a terminal commandline and find the partitions you want to use. The easiest way to use them will be to copy and paste from the terminal to the file.That means files can be images, text documents, executables, and much more. Most files are organized by keeping them in individual folders. In Python, a file is categorized as either text or binary, and the difference between the two file types is important.

Text files are structured as a sequence of lines, where each line includes a sequence of characters. This is what you know as code or syntax. It ends the current line and tells the interpreter a new one has begun.

A backslash character can also be used, and it tells the interpreter that the next character — following the slash — should be treated as a new line. A binary file is any type of file that is not a text file. In other words, they must be applications that can read and interpret binary. In order to open a file for writing or use in Python, you must rely on the built-in open function.

As explained above, open will return a file object, so it is most commonly used with two arguments. An argument is nothing more than a value that has been provided to a function, which is relayed when you call it. The second argument you see — mode — tells the interpreter and developer which way the file will be used.

The current information stored within the file is also displayed — or printed — for us to view. Once this has been done, you can move on to call the objects functions. The two most common functions are read and write. Naturally, if you open the text file — or look at it — using Python you will see only the text we told the interpreter to add.

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If you need to extract a string that contains all characters in the file, you can use the following method:. The output of that command will display all the text inside the file, the same text we told the interpreter to add earlier. For example, with the following code the interpreter will read the first five characters of stored data and return it as a string:.

How to change the permission of a directory using Python?

If you want to read a file line by line — as opposed to pulling the content of the entire file at once — then you use the readline function. You would execute the readline function as many times as possible to get the data you were looking for.

Each time you run the method, it will return a string of characters that contains a single line of information from the file. If we wanted to return only the third line in the file, we would use this:. But what if we wanted to return every line in the file, properly separated? You would use the same function, only in a new form.

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This is called the file. Notice how each line is separated accordingly? Note that this is not the ideal way to show users the content in a file. When you want to read — or return — all the lines from a file in a more memory efficient, and fast manner, you can use the loop over method.In a previous article, we showed you how to create a shared directory in Linux. There are two possible methods of doing this: the first is using ACLs Access Control Lists and the second is creating user groups to manage file permissionsas explained below.

Make sure all commands are executed as root user or use the the sudo command with equivalent privileges. First, check the current file system type on your system, and also whether the kernel supports ACL as follows:. Next, check if the file system partition is mounted with ACL option or not:. From the above output, we can see that default mount option already has support for ACL. If the user already has a default user group normally with same name as usernamesimply change the group owner of the directory.

However, this will c reate a shared directory :. Then add the user tecmint to the group projects as follows:. If any issues, do ask via the comment section below.

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View all Posts. Aaron Kili is a Linux and F. S enthusiast, an upcoming Linux SysAdmin, web developer, and currently a content creator for TecMint who loves working with computers and strongly believes in sharing knowledge. Your name can also be listed here. Got a tip? Submit it here to become an TecMint author. Your email address will not be published. Save my name, email, and website in this browser for the next time I comment.

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Notify me of followup comments via e-mail.You need to know a handful of commands for working with permissions. The following table shows a list. You can use the —l switch to check permissions them when you use the ls command to list the files in a folder.

But what if you want to change them? To use chmod to change file permissions, you have to tell it three things:.

how to give read and write permission to a file in python

In the following sections, this command is broken down. You have to start the command with sudo. Use them if you want to add or remove a permission. For example, you can change the write permission only and leave the read and execute permissions alone. The following table shows you which letters to type to select the different permissions.

This part is easy. You can look inside a folder only if you can execute it. You can rename a file only if you can execute it.

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As long as you can read a file, you can run it as code if it gets passed to some other app. Sometimes permissions fail silently. Nothing appears on the screen. Permissions are complicated, so you need to practice them.

Give permissions to files and folders in Windows 10

Say that you want to set permissions so that everyone who uses your Pi can write a file. Can you work out what the command should be? Assume that everyone can read it already.

The following figure shows a before-and-after so that you can see how this command changes the permissions string when you use the ls command. After the command, everyone can edit the file.

Reading and Writing Files in Python

Sometimes permissions look like numbers. For example, blog articles and books sometimes tell you to set the permissions on a file to or or some other number. But what do they mean?

The first number sets your personal permission, the second number is the group permission, and the third number is the everyone else permission. So this is really just another way to write rwx three times.

The following table shows you how to convert between a three-letter permission string into a single number. If you want to change all the permissions inside a directory, you can change them for every file by hand — which can take a very long time.Get the latest tutorials on SysAdmin and open source topics. Write for DigitalOcean You get paid, we donate to tech non-profits. DigitalOcean Meetups Find and meet other developers in your city.

Become an author. Python is a great tool for processing data.

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It is likely that any program you write will involve reading, writing, or manipulating data. For example, consider a Python program that checks a list of users for access control. Your list of users will likely be stored and saved in a text file. Perhaps you are not working with text, but instead have a program that does financial analysis. In order to do some number crunching, you will likely have to input those numbers from a saved spreadsheet.

Regardless of your application, it is almost guaranteed that inputting or outputting data will be involved. This tutorial will briefly describe some of the format types Python is able to handle. For this tutorial, you should have Python 3 installed as well as a local programming environment set up on your computer. If this is not the case, you can get set up by following the appropriate installation and set up guide for your operating system:.

Python is super accommodating and can, with relative ease, handle a number of different file formats, including but not limited to the following:. Before we can begin working in Python, we need to make sure we have a file to work with. In the new file, enter a few lines of text.

Next, save your file and make sure you know where you put it. This will be very important in later steps, where we open the file in Python. Before we can write our program, we have to create a Python programming file, so create the file files.

To make things easy, save it in the same directory as our days. To open a file in Python, we first need some way to associate the file on disk with a variable in Python. This process is called opening a file. We begin by telling Python where the file is. The location of your file is often referred to as the file path.

In order for Python to open your file, it requires the path. The path to our days. In Python, we will create a string variable to store this information. In our files. The open function requires as its first argument the file path.

The function also allows for many other parameters.It can sometimes be necessary to change file and folder permissions on your Mac, usually because you want to restrict access to certain users and groups.

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This article shows you how to change file permissions on files just using Terminal. Barrett as a great starting point. File permissions permit users different types of permissions to read and write files. You might even want to delete all permissions for a particular user so that the file cannot even be opened though it will still be visible in Finder.

To make files invisible, follow this tutorial. Through Terminal, you have a lot of control over permissions, but at a basic level you can set them in Finder as follows:. Add or delete user names under the Name column and choose the permissions you want under the Privilege column.

Now that you know how to edit permissions in Finder, read on to find out how it can be done in Terminal. For example:. Navigate to the folder where the file, folder or application you want to change resides. Note that you will need to use quotes around filenames only if the item you want to edit contains a space, as it does in this case. You should see the list of files in the current directory along with all the relevant file permissions for each item in the directory, as shown below.

In the leftmost column, the file permissions for each item are listed. The next step is to actually change the file permissions to whatever you want. The chmod command runs in two modes — absolute and symbolic mode.

The absolute mode uses an octal number with various values that can be combined to set many of the different read, write and execute permissions at once.

To change the file permissions on a file, you need to specify the category User, Group, Others, or all threethe type of operation e. In my example, this is how it looks:. Thankfully, chmod can act on multiple files.Joinsubscribers and get a daily digest of news, geek trivia, and our feature articles.

This command modifies Linux file permissions, which look complicated at first glance but are actually pretty simple once you know how they work.

how to give read and write permission to a file in python

In Linux, who can do what to a file or directory is controlled through sets of permissions. There are three sets of permissions. The permissions control the actions that can be performed on the file or directory. They either permit, or prevent, a file from being read, modified or, if it is a script or program, executed.

For a directory, the permissions govern who can cd into the directory and who can create, or modify files within the directory. To see what permissions have been set on a file or directory, we can use ls.

We can use the -l long format option to have ls list the file permissions for files and directories. On each line, the first character identifies the type of entry that is being listed. If it is a dash - it is a file.

how to give read and write permission to a file in python

There are three characters in each set of permissions. The characters are indicators for the presence or absence of one of the permissions. They are either a dash - or a letter. If the character is a dash, it means that permission is not granted. If the character is an rwor an xthat permission has been granted.

In our screenshot, the first line starts with a d. The next three characters are the user permissions for this directory. These show that the owner has full permissions. The rwand x characters are all present.

This means the user dave has read, write and execute permissions for that directory. The second set of three characters are the group permissions, these are r-x. These show that the members of the dave group have read and execute permissions for this directory. That means they can list the files and their contents in the directory, and they can cd execute into that directory. They do not have write permissions, so they cannot create, edit, or delete files.

These permissions apply to people who are not governed by the first two sets of permissions. So, to summarise, group members and others have read and execute permissions.