AlmaLinux

Differences Between source xxx.sh and ./xxx.sh in Linux

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Differences Between source xxx.sh and ./xxx.sh in Linux

Both source xxx.sh and ./xxx.sh are common methods for executing Shell scripts in Linux/Unix systems, and they have fundamental differences in execution environment, permission requirements, and their impact on the current Shell. The table below summarizes their core differences for easier understanding: Feature Comparison <span>source xxx.sh</span> <span>./xxx.sh</span> Execution Environment Current Shell Process New Sub Shell … Read more

The Stories of Linux Operations: The Servers We Pursued Over the Years

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The Stories of Linux Operations: The Servers We Pursued Over the Years

Do you remember the nervousness of typing the ls command for the first time? That black-and-white terminal window felt like a gateway to a new world. Twenty years ago, who would have thought that this group of geeks tinkering with the ‘penguin system’ would become the invisible guardians of the internet age? The Rise from … Read more

Understanding Linux Black Hole and Zero Bytes: A Comprehensive Guide to /dev/null and /dev/zero

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Understanding Linux Black Hole and Zero Bytes: A Comprehensive Guide to /dev/null and /dev/zero

If you often browse the default files in Linux, you must have an impression of /dev/null and /dev/zero, or you might have seen shell code like this:> /dev/null 2>&1. It is a special character device file in the Linux system, commonly referred to as the “null device” or “black hole device.” It occupies a fixed … Read more

A Brief Overview | File Handles in Linux Systems – Knowledge Points Learning

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A Brief Overview | File Handles in Linux Systems - Knowledge Points Learning

This article mainly explains the knowledge related to file handles in Linux (File Handle) and commands. A file handle (FD) is a non-negative integer that serves as anindex, allowing a process to find the corresponding information of anopen file in itsfile descriptor table. Essentially, it is an abstract reference to all I/O resources, representing not … Read more

Linux KSMBD Subsystem Vulnerability Can Exhaust Server Resources

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Linux KSMBD Subsystem Vulnerability Can Exhaust Server Resources

Recently, a denial-of-service vulnerability was discovered in the KSMBD (SMB Direct) subsystem of the Linux kernel, attracting widespread attention in the open-source community. This vulnerability, identified as CVE-2025-38501, allows remote and unauthenticated attackers to exploit the kernel’s handling of half-open TCP sessions to exhaust all available SMB connections. The key aspect of this vulnerability is … Read more

Essential Linux Commands for Bioinformatics Analysis: zip, gzip, bzip2, tar

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Essential Linux Commands for Bioinformatics Analysis: zip, gzip, bzip2, tar

Hello, Linux novice adventurer! Do you often encounter large files taking up space, or have a bunch of scattered files that need organizing? Don’t worry! Today, we will discuss the four “compression and packaging tools” in Linux: zip, gzip, bzip2, and tar. They act like your file “weight loss coach” and “moving captain,” helping you … Read more

Detailed Explanation of Disk Performance Testing with the dd Command in Linux

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Detailed Explanation of Disk Performance Testing with the dd Command in Linux

1. Common Parameters of the dd Command 1.1 Basic Input/Output Parameters if=filename: Specifies the input file path; of=filename: Specifies the output file path; ibs=bytes/obs=bytes: Sets the input/output block size (in bytes) for a single operation, where bs can cover both (commonly used); 1.2 Block Control Parameters bs=size: Sets the read/write block size uniformly (e.g., 1M, … Read more

Post-Penetration on Linux: Various Methods for Credential Collection (Part 1)

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Post-Penetration on Linux: Various Methods for Credential Collection (Part 1)

tcpdump Use tcpdump to capture traffic from all network interfaces in real-time, filtering and saving when sensitive information is detected in the traffic. tcpdump -i any -s 0 -A -n -l |egrep -i "Host:|Authorization:|password:|password=" • -i any: Listen to traffic on all network interfaces; • -s 0: Capture full packets (no truncation); • -A: Display … Read more

Example of Linux Packaging and Deployment Script

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Example of Linux Packaging and Deployment Script

In Linux systems, we often need to create scripts, upload them to production servers, deploy the scripts, grant permissions, and then create jobs. If the company has deployed Ansible automation tools, batch deployment can be handled. If there are no automation tools like Ansible, we can package/install/deploy scripts through scripts to avoid manual handling on … Read more

A Beginner’s Guide to Using Firewalld in Linux Systems

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A Beginner's Guide to Using Firewalld in Linux Systems

What is Firewalld? It is a front-end management tool for the Linux kernel’s Netfilter/iptables system. It provides a more user-friendly interface for managing firewall rules, simplifying the complexity of directly using iptables. Firewalld supports dynamic updates, allowing modifications to rules without restarting the service, and introduces the concepts of “zones” and “services” for quickly switching … Read more