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We know that a shared library is a library that can be linked to any program at runtime. In order to view all the shared libraries used by an executable we make use of the Linux command utility known as ldd. We can easily locate the shared libraries on a Linux machine, as they usually start with lib* prefix and have extensions like .so (shared object). Let's first understand and see examples of how to make use of the ldd command that Linux provides us with. ldd is a command utility that Linux provides us with and is ... Read More
Shared memory is a method of inter-process communication (IPC) where multiple processes can access the same region of physical memory. It allows cooperating processes to exchange data by reading and writing to a common memory segment, making it one of the fastest IPC mechanisms available. In shared memory systems, processes communicate by establishing a shared memory region in their address space. When one process wants to share data, it creates this shared region and stores the information there. Other processes can then attach to this shared memory segment to read or modify the data. How Shared Memory Works ... Read More
Graphical User Interface (GUI) is an interface that allows users to interact with different electronic devices using icons, visual indicators, and graphical elements. The graphical user interfaces were created because command line interfaces were quite complicated and it was difficult to learn all the commands in it. In today's times, graphical user interfaces are used in many devices such as mobiles, MP3 players, gaming devices, smartphones, desktop computers, and tablets. The GUI acts as an intermediary layer between the user and the underlying operating system, translating user interactions into system commands. GUI Position ... Read More
In Operating System, the fork() system call is used by a process to create another process. The process that uses the fork() system call is the parent process and the process consequently created is known as the child process. Process A process is an active program — a program that is under execution. It is more than just the program code as it includes the program counter, process stack, registers, program code, and other runtime information. The program code itself is only the text section of a process. A process changes its state as it executes, depending ... Read More
ARP (Address Resolution Protocol) is a networking protocol that maps network addresses, such as IP addresses, to physical MAC addresses. It is a fundamental component of network communication, enabling devices to locate each other on the same network segment. The arp command provides various options for viewing and managing the ARP cache. How ARP Works When a device needs to communicate with another device on the same network, it broadcasts an ARP request asking "Who has this IP address?" The target device responds with its MAC address, and this mapping is stored in the ARP cache for future ... Read More
After installing minimal version of RHEL/CentOS 7, you might be wondering what to do next. The minimal installation provides you with a basic operating system, but you still need to install additional packages and configure the system to suit your needs. In this article, we will explore 25 essential tasks to do after a minimal RHEL/CentOS 7 installation to help you get started. System Updates and Core Setup 1. Update the System First thing to do after installing a minimal RHEL/CentOS 7 is to update the system. This ensures you have the latest security updates and bug ... Read More
Network emulation (netem) is a Linux kernel component that provides network emulation functionality for testing protocols by simulating real-world network conditions like delays, packet loss, and reordering. It emulates the properties of wide area networks, making it invaluable for network testing and protocol development. The current stable version of netem allows emulation of variable delay, packet loss, packet reordering, and packet duplication. This makes it possible to test how applications and protocols behave under various network conditions without requiring actual network infrastructure. Enabling netem There are two ways to use the network emulator. First, you can enable ... Read More
Operating systems manage different types of processes during their lifecycle. Three important categories are zombie processes, orphan processes, and daemon processes. Each serves a different purpose and behaves uniquely in the system. Zombie Processes A zombie process is a process whose execution has completed but still has an entry in the process table. This occurs because the parent process needs to read the child's exit status before the process can be fully removed from the system. Zombie Process Lifecycle Parent Running Child Running ... Read More
The ps command is a powerful tool used for monitoring processes in Linux operating systems. It stands for process status and displays information about processes currently running on a system. This information is useful for troubleshooting, optimizing performance, and identifying potential security issues. Below are 25 useful ps command examples for effective Linux process monitoring. Basic Process Listing Display All Running Processes ps aux This displays all processes with detailed information including PID (process ID), CPU usage, memory usage, user, and command. Show Process Tree Structure ps auxf The ... Read More
In Linux, the sort command is a powerful utility for arranging file contents in a specific order. By default, it sorts lines alphabetically based on ASCII values. However, the basic sort command only displays sorted output without modifying the original file. To sort a file in-place (modifying the original file), we need specific techniques. Understanding the Sort Command The sort command operates line by line, treating each line as a record. Key characteristics include − Sorts one line at a time from the input Displays file contents similar to the cat command when applied to files ... Read More