Ubuntu on MeerStory

Check Linux Logged-in Users and Server Load at a Glance! Practical Guide to the w Command

Wed, 07 Oct 2026 15:31:40 +0900

Overview

In server monitoring and user session management, the w command is an essential tool for immediately understanding currently logged-in users and system load (Load Average). In this article, we will examine everything step by step, from interpreting the basic output of the w command to frequently used option combinations in practice and the differences between who and uptime.

1. Checking Active Users and System Load at a Glance: Basic w Execution

Run the uptime command to compare and check the system uptime and load information, which matches the first line of the w command output.

Ubuntu SSH Complete Practical Guide - From Connection to Port Forwarding and Security Configuration in One Go

Wed, 07 Oct 2026 15:24:45 +0900

Overview

SSH (Secure Shell) is an essential standard network protocol for managing remote Linux servers. In this article, we will walk step-by-step through setting up an OpenSSH server on Ubuntu, passwordless public key authentication, SSH port forwarding for practical networking, and essential security hardening tips.

1. Installing OpenSSH Server and Enabling the Service

Update the latest package list and install the openssh-server package to provide remote access services on the Ubuntu system.

The Core of Automatic Linux File Permission Control! Practical umask Configuration and Complete Guide

Wed, 07 Oct 2026 15:17:43 +0900

Overview

In a Linux environment, we examine the underlying operating principles of umask, which determines default access permissions for newly created files and directories. From octal calculation methods to shared directory permission control and persistent configuration via shell profiles, this guide covers essential management techniques ready for production use.

1. Checking the Current umask and Testing Default File and Directory Creation Permissions

Execute the mkdir -p /tmp/umask-lab && cd /tmp/umask-lab command to create and move into a dedicated practice directory for testing umask settings and permissions.

Complete Linux lsof Guide - Practical Tips from Port Conflicts to Reclaiming Deleted File Disk Space

Wed, 07 Oct 2026 15:08:55 +0900

Overview

Issues such as “port conflicts” or “disk space not freeing up after deletion” that occur during Linux system administration can be resolved immediately using the lsof command. In this article, we explore essential techniques for applying lsof in practical environments, where everything is handled as a file in Linux. We will walk through step-by-step troubleshooting know-how essential for system engineers, from port tracking to releasing file locks.

Basic lsof Verification and Checking Open Files by Specific Users/Processes

To check if the lsof command is installed on the system and install the package if it is missing, run the command command -v lsof >/dev/null 2>&1 || (apt-get update -qq && apt-get install -y lsof).

Essential When Linux Servers Stutter! Perfect Process Priority Control with the nice Command

Wed, 07 Oct 2026 15:02:21 +0900

Overview

In environments with limited server resources, running background tasks or heavy batch scripts can degrade the responsiveness of core services. In this post, we will explore practical tips for managing CPU scheduling priority using the nice and renice commands to maintain system stability.

1. Checking Process Priority (NI/PR) and Setting Up an htop Monitoring Environment

Install the essential htop and procps packages to set up the practice environment for monitoring process priority.

Complete Guide to the Linux cut Command - Effortlessly Extract Only the Desired Columns from Log and CSV Text Data!

Wed, 07 Oct 2026 14:55:34 +0900

Overview

When you need to quickly extract specific columns from large log files or CSV data in a Linux environment, the cut command is the lightest and most powerful tool available. In this guide, we will explore essential hands-on techniques, from delimiter-based field extraction to fixed-width byte/character slicing, that you can immediately apply in real-world scenarios.

Extracting CSV and System Account Data Using Delimiters (-d) and Fields (-f)

Run the command mkdir -p ~/cut_demo && cd ~/cut_demo to create a dedicated directory for hands-on practice with the cut command and navigate into it.

Everything About Listing Files in Linux - Mastering Essential ls Command Options for Daily Work

Wed, 07 Oct 2026 14:50:31 +0900

Overview

We will explore core practical use cases for ls, the most fundamental and frequently used file listing command in a Linux environment. Moving beyond basic output limitations, we summarize real-world techniques to maximize your workflow efficiency—from checking hidden files and viewing detailed permissions to sorting by timestamp and file size.

1. Basic Listing and Viewing Hidden Files (ls, ls -a)

Execute the mkdir -p ~/ls_demo && cd ~/ls_demo command to create an isolated workspace for practicing ls commands and navigate into that directory.

Slow Linux Boot Time? Find and Optimize Bottleneck Services in 3 Minutes with systemd-analyze

Wed, 07 Oct 2026 14:44:45 +0900

Overview

If your Linux server or PC takes longer to boot than usual, identifying the cause is essential to reducing unnecessary delays. Using the systemd-analyze command, you can effortlessly measure total boot time, trace bottleneck services, and verify unit files. This article covers key analytical commands and performance optimization techniques you can immediately put into practice.

1. Checking Boot Duration and Measuring Staged Delays (time & blame)

The systemd-analyze command measures and displays the overall time elapsed during the boot process, broken down into kernel and userspace initialization.
Looking at the execution result, you can confirm that it took a total of 315ms for the system to boot up and reach the graphical environment graphical.target.
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Linux unzip Complete Guide: From Extraction to Fixing Korean Character Encoding Issues

Wed, 07 Oct 2026 14:39:37 +0900

Overview

This guide introduces the basic usage and essential practical options of the unzip command, frequently used for extracting ZIP archives in Linux environments. Step-by-step instructions cover everything from previewing archive contents and extracting to specific directories to fixing broken character encodings for files created in Windows.

Installing the unzip Package and Preparing a Test Archive

To compress and extract archives in an Ubuntu environment, install the necessary packages using the sudo apt-get update -qq && sudo apt-get install -y unzip zip command.