Basic concurrency with fork()

Wed, 23 Jun 2021 00:00:00 +0000

When programming on Linux/Unix, the function fork(2) allows us to create new processes. This is a short and example-driven introduction to the basics of using that function.

First stab

After a brief look at the manual page for fork(2) we can tell that it returns a value of type pid_t and does not take any arguments:

NAME
     fork – create a new process

SYNOPSIS
     #include <unistd.h>

     pid_t
     fork(void);

Let us simply call fork and see what happens and what values does it return.

Reading and monitoring files on Linux

Sat, 19 Jun 2021 00:00:00 +0000

Let’s start with something super basic. To print the contents of a file you can use cat:

cat file

This tool is simple but really powerful when combined (piped) with other commands. However, cat is not very practical if you just want to see the contents of a larger file. In that case you can use less, which also allows you to conveniently browse your file:

press space for page down or b for page up,
type /pattern to search for pattern in the file (n jumps to the next occurence, while N jumps to the previous one),
press q to quit.

If you need to watch a certain file (typically a log file), you can simply use tail -f:

Linux on Artur Meski

Basic concurrency with fork()

First stab

Reading and monitoring files on Linux