I am building a Blazor application with a REST API and Web interface. I will also have a monitoring part of the application that will poll data each second from a lot of different data sources. I have created a long running thread in a separate class that simply polls the data I want and it seems to be working fine. The application template I am using is a Blazor ASP.NET Server application. Simply like this:
I have an application, written in Python, which is used by a fairly technical audience (scientists).
In Unix whenever we want to create a new process, we fork the current process, creating a new child process which is exactly the same as the parent process; then we do an exec system call to replace all the data from the parent process with that for the new process.
From the post Why can rm remove read-only files? I understand that rm just needs write permission on directory to remove the file. But I find it hard to digest the behaviour where we can easily delete a file who owner and group different.
I know that “Everything is a file” means that even devices have their filename and path in Unix and Unix-like systems, and that this allows for common tools to be used on a variety of resources regardless of their nature. But I can’t contrast that to Windows, the only other OS I have worked with. I have read some articles about the concept, but I think they are somewhat uneasy to grasp for non-developers. A layman’s explanation is what people need!
My question is how directories are implemented? I can believe a data structure like a variable e.g. table, array or similar. Since UNIX is Open Source I can look in the source what the program does when it created a new directory. Can you tell me where to look or elaborate on the topic? That a directory “is” a file I could understand and is a directory really a file? I’m not sure that it is true that files are stored “in” files while still in way you could say the word file about nearly anything and I’m not sure what absolutely not is a file since you could call even a variable a file. For example a link is certainly not a file and a link is like a directory but then this violates that a directory is a file?
Preface: I love bash and have no intention of starting any sort of argument or holy-war, and hopefully this is not an extremely naive question.
It’s a question about user space applications, but hear me out!
Will the executable of a small, extremely simple program, such as the one shown below, that is compiled on one flavor of Linux run on a different flavor? Or would it need to be recompiled?
I am trying to understand how user permissions work in Linux. The kernel boots and starts init as root, right? Init then runs startup scripts and runs getty (agetty), again as root. Agetty just reads user name and runs login, still as root, I think. Nothing interesting yet. But what does login do? I wasn’t able to find anything better than “it attempts to log in”. Suppose login finds that password matches (and we trying to log in as usual user), how does it change user id? I thought that there should be system call for that but I wasn’t able to find it (maybe I’m just blind?)