Linux make file readonly

Question: How Do I Make A File Read Only In Linux

chmod ugo+rwx foldername to give read, write, and execute to everyone. chmod a=r foldername to give only read permission for everyone.

How do I make a file read only in Unix?

You can use the chmod command to set read-only permission for all files on a Linux / Unix / macOS / Apple OS X / *BSD operating systems.

How do I make a file not editable in Linux?

Method #1: You can make file readonly by removing users’ write permission for a file. Under Linux and UNIX user cannot remove or modify file if they don’t have a write permission. You can use normal chmod command for this purpose.

What is the meaning of chmod 777?

Setting 777 permissions to a file or directory means that it will be readable, writable and executable by all users and may pose a huge security risk. File ownership can be changed using the chown command and permissions with the chmod command.

How do you make a file read only?

Save as read only Click the Microsoft Office Button. , and then click Save or Save As if you have previously saved the document. Click Tools. Click General Options. Click the Read-only recommended check box. Click OK. Save the document.

What does chmod 666 do?

chmod 666 file/folder means that all users can read and write but cannot execute the file/folder; chmod 777 file/folder allows all actions for all users; chmod 744 file/folder allows only user (owner) to do all actions; group and other users are allowed only to read.

What does — R — mean in Linux?

File Mode. The r letter means the user has permission to read the file/directory. And the x letter means the user has permission to execute the file/directory.

How do I make a file Undeletable in Linux?

To make a file undeletable by any system user, including root, you need to make it unmodifiable using using the chattr command. This command changes file attributes on a Linux file system.

How do I make a file not editable?

To make a document un-editable, first, select all the text in the document by pressing Ctrl+A. Once all of the text is highlighted, click “Restrict Editing” in the “Protect” group on the “Developer” tab.

Is readonly add to override?

To save a file that’s read-only, use the following command: :wq! The exclamation point after write-quit is to override the read-only status of the file.

What does chmod 555 do?

What Does Chmod 555 Mean? Setting a file’s permissions to 555 makes it so that the file cannot be modified at all by anyone except the system’s superuser (learn more about the Linux superuser).

How do I send chmod 777 to a file?

If you are going for a console command it would be: chmod -R 777 /www/store . The -R (or –recursive ) options make it recursive. chmod -R 777 .

What does chmod 644 mean?

Permissions of 644 mean that the owner of the file has read and write access, while the group members and other users on the system only have read access.

Why are all my Word documents read only?

Are the file properties set to read-only? You can check the file properties by right-clicking on the file and choosing Properties. If the Read-only attribute is checked, you can uncheck it and click OK.

How do I change a file from read only to edit?

Read-only Files Open Windows Explorer and navigate to the file you want to edit. Right-click the file name and select “Properties.” Select the “General” tab and clear the “Read-only” check box to remove the read-only attribute or select the check the box to set it.

Why does my folder keep going back to read only?

If your folder keeps reverting to read-only it could be due to a recent Windows 10 upgrade. Many users have reported that when upgraded their system to Windows 10, they encountered this error. Read-only is a file/folder attribute which lets only a specific group of users read or edit the files or folder.

What does chmod 444 do?

444 = (r– r– r–): owner/group/others are all only able to read the file. They cannot write to it or execute it. If you were able to set to 644 the owner (you) could modify the file while all others would be restricted. In that case you would not need to change permissions in order to modify it.

What is the meaning of chmod 775?

The chmod 775 is an essential command that assigns read, write, and execute permission to a specific user, group, or others.

What does chmod 770 do?

770 means owner and group have full permissions. 777 means all (user group other) have full permissions on this directory.

What does R mean in bash?

bash. I learned that -r means recursive, which means the command can be performed in all subdirectories.

What does P mean in Linux?

-p is short for –parents – it creates the entire directory tree up to the given directory.

How do I chmod files in Linux?

To change directory permissions in Linux, use the following: chmod +rwx filename to add permissions. chmod -rwx directoryname to remove permissions. chmod +x filename to allow executable permissions. chmod -wx filename to take out write and executable permissions.

What is immutable file in Linux?

$ lsattr /etc/passwd. Once the file is set immutable, this file is impervious to change for any user. Even the root cannot modify, remove, overwrite, move or rename the file. You will need to unset the immutable attribute before you can tamper with the file again.

How use chattr command in Linux?

The chattr command in Linux is a file system command which is used for changing the attributes of a file in a directory. The primary use of this command is to make several files unable to alter for users other than the superuser.

How do I make a document editable?

Enable editing in your document Go to File > Info. Select Protect document. Select Enable Editing.

How do I make a Notepad file not editable?

GUI Method. Right click on the file, you want to make it Read-only. Click on the Properties tab from the context menu. Click the Read-only check box belong to Attributes from on the General tab from the popped up Properties window.

How do I make a PDF read only?

To create a read-only version of a PDF, open the file using Adobe Acrobat. Open Document Security dialog box by clicking File -> Properties and choose Security tab in Document Properties pop-up window. By default, PDF has no security settings, and Security Method shows No Security.

Related Posts

1. How To Use Chmod In Linux
2. Question: How Does Chmod Work In Linux
3. Why We Use Chmod In Linux
4. Quick Answer: Can Linux Read Windows File System
5. Quick Answer: What Is Chmod 775 Command In Linux
6. Quick Answer: What Is Chmod 755 Command In Linux
7. Why We Use Chmod Command In Linux
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12. Question: How Do I Read File Permissions In Linux
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make file appear readonly to a library function

I’m using a library that can read or write some metadata that I need from files. I only need to read and I know that my files are on slow storage. I noticed that while reading the values I need is very fast, closing the files is slow. Basically, if I open(); read(); close() each file my program is quite slow, but if I only open(); read() during operation and close() right before exit (i.e. I let my run-time close the files during finalization of the leaked objects) the program runs fast, but stops for several seconds just before exit — when the files are being closed. On the other hand, if I remove write permission from the files this doesn’t happen: it seems that files open readonly are closed much faster than the files open read-write. It could be that the library writes metadata on close «just to be sure» if the file is writable, or some other reason, but anyway — it’s impossible to specify for the library that I wan’t to open the file only for reading: it tries to be intelligent and decides based on file permissions. At the moment to speed things up I’m changing file permissions just before opening it and restoring permissions after the metadata is read. It works, but it feels wrong. Is there a way in linux / unix to make files appear readonly to the current process temporarily? I can’t use setuid(2) because the program is ran by unpriviledged user (or am I wrong about this?). details The library is taglib-ruby which is in turn a wrapper around taglib’s C++ API. The program may list the tracks on the device and needs to know their length in seconds (the reason I use taglib), but the same media will be written to (new tracks uploaded, some tracks deleted) hence I can’t just force users to mount the device readonly. I realize that a better solution would be patching taglib to allow to specify that I just want to read the metadata, then patch taglib-ruby to wrap the new API. But I’m not up to it, plus I have a workaround already, thus not much insetive to go down that route. I’m just wondering if there is a better workaround.

Is it the library that calls the open() function, or is it you opening the file and passing a FILE * as argument to functions from the library?

remount the directory using «-bind,ro» switch. And ask taglib to operate on read-only filesystem. It should stop library from opening file in write mode.( not sure if -bind switch is supported on all distributions )

Sorry, I don’t understand. You access the file and then the atime is updated on a close() . This causes a write() to the file system. Also: relatime. At the very least, you can rule out atime by a mount with noatime. Mounting with ro will have the same effect as per Icarus3. I guess the library maybe re-writing something; is the modified time updated? At least that could provide helpful information.

As well strace -e trace=open,write,close might be helpful. You will get a brief overview of what is being written, if that is the case.

IOStream * stream = new FileStream («/path/to/file», true);//true means open in read mode only File * file = new File( stream ); //constructor is protected, so extend File class FileRef fileref( file ); //now use fileref.

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Make file in linux readonly

Is there a way to make a file readonly permanently in linux. Or can I put a password to a file to make it readonly, then apply that password again to change its permission, or before they can alter it.

Like it’s pointed out by Sami-Laine , you can’t. However, if you’re the admin & the person to know the root password you can. And not to mention recovering root password when you’ve access to hardware.

Not really, you could use chmod 600 to make the file only read/writeable by you (and root) or do chown root:root so that only root password can change permissions. Either that or encrypt the file.

Who are you protecting against, or in other words, who would still be allowed to make the file read-write? You can’t do anything that the system administrator or someone with physical access can’t undo.

2 Answers 2

Only way to do that would be to write the file in question on a media which is writable only once, e.g. a CD-ROM.

Any other solution is possible to circumvent by root. If the file you’d like to make non-writable is one of system files, e.g. /etc/passwd , you’d either have to to live with many files being read-only or create a symlink from the file you want to protect, e.g. /etc/passwd to a file residing on your read-only media, but that again would be easy to circumvent by root , simply delete the symlink and create new content in its place.

So simple answer would be: No and there must be a better way of achieve whatever it is that you want to accomplish by making one or more files permanently read-only.

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