adb modify file permissions

1. adb View file read and write permissions

You can use the adb shell ls -l command to view the read and write permissions of a file or folder.

For example, to check the permissions of the folder /sdcard/myfolder, you can use the following command:

adb shell ls -l /sdcard/myfolder

The system displays detailed information about the folder, including permission information. For example:

drwxrwxrwx root     root              1970-01-01 00:00 myfolder

In this example, the leading d indicates that this is a folder, and the trailing rwxrwxrwx indicates the permissions of the folder:

The first character indicates the file type (d for directory, – for normal file)
The 2nd to 4th characters indicate the permissions of the file owner (rwx means readable, writable, executable)
The fifth to seventh characters indicate the permissions of the group in which the file is located (rwx for readable, writable, and executable).
The 8th to 10th characters indicate permissions for other users (rwx for readable, writable, executable)
In this example, the folder /sdcard/myfolder has permissions of readable, writable, and executable for either the file owner, the group the file is in, or another user.

Finally, note that if you encounter a permissions error when executing the ls -l command, you may need to use the su command before the adb shell to cut the

2. adb Modify folder to writable permissions

You can use the adb shell chmod command to modify the permissions of a file or folder.

For example, to change the permissions of the folder /sdcard/myfolder to writable, you can use the following command:

adb shell chmod -R 777 /sdcard/myfolder

This will change the permissions of /sdcard/myfolder and all its subfiles and subfolders to readable, writable, and executable.

Please note that in Android, you need to have sufficient privileges to execute the chmod command when using the adb shell. Therefore, if you encounter a permissions error while executing this command, you may need to switch to the root user using the su command before the adb shell, as shown below:

adb shell su -c "chmod -R 777 /sdcard/myfolder"

Finally, please note that such permission modifications may affect the security of the system and should be used with caution.

3. What do the file owner, file group, and other users refer to?

On Linux systems, files and directories have owners and groups.

File owner (owner) refers to the owner of a file or directory. The owner has the highest privileges and can perform any operation on the file or directory.

Group refers to the group to which a file or directory belongs, and users in the group have certain permissions to perform specific operations on the file or directory.

Other users refer to users other than the file owner and the group in which the file resides; these users usually have the lowest privileges and can only perform specific actions.

File and directory permissions on Linux systems are differentiated by user identity and user group identity. Each file or directory has three sets of permissions: the permissions of the file owner, the permissions of the group in which the file resides, and the permissions of other users.

4. If I want to delete a folder, do I need to change the permissions of this folder or its parent directory?

If you want to delete a folder, you need to modify the permissions of this folder. This is because, on Linux systems, if you want to delete a folder, you must delete all of its contents before you can delete the folder itself. Files or directories in a folder can be deleted if they have write permissions. However, if the files or directories in a folder do not have write permissions, they cannot be deleted, so you need to change the permissions on the folder.

Changing the permissions of the parent directory does not solve the problem of deleting the folder, because if you change the permissions of the parent directory, you still need to have write permissions to the folder in order to delete the folder.

To delete a folder, use the Linux command rm -r. For example, to delete a folder named mydir, use the command rm -r mydir.