How to change read only permissions on a file in linux changin permissions for a file

as you know about linux, you can restrict access to a file, for example, you (as the owner) might want to be permitted to read a letter but not to change it in anyway. to prohibit changes, you remove the write permissions for that file:

changing the permissions, removing the write permission of the a file called my_users by typing:

chmod -w my_users