bash

All posts tagged bash by Linux Bash
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    Learn how to host multiple websites on a single Linux server by running multiple Apache instances with distinct configurations using Bash. This approach offers improved application isolation, enhanced security, and tailored resource allocation, facilitating efficient server management. Follow a step-by-step guide covering Apache installation, configuration duplication, service file creation, and final validation for effective multi-instance management.
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    Learn how to create a password-protected directory in Linux using the Apache server, `.htaccess`, and `.htpasswd`. This tutorial guides you from installing Apache and necessary utilities, through setting up directories and password files, to configuring server settings and testing your configuration for secure data access.
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    This guide explores optimizing WordPress performance on a Linux server using Apache. Key approaches include enabling compression and browser caching, tuning WordPress configurations, and optimizing the MySQL database. Additionally, it covers automating maintenance with Bash scripts, all aimed at enhancing site speed, user experience, and SEO rankings.
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    This article guides Linux developers on enabling CORS (Cross-Origin Resource Sharing) on their servers using Bash scripting. It details CORS configuration steps for Apache and Nginx, including editing server files and adding necessary headers. Additionally, it covers testing CORS settings with tools like curl and automating configurations through Bash scripts, ensuring smooth functionality for web applications accessing resources across different domains.
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    This article explains how to accurately log client IP addresses from the `X-Forwarded-For` header in environments using proxies, utilizing Linux Bash. It covers the basics of the header, parsing methods using Bash, and addresses challenges such as IP spoofing and multi-IP headers to enhance security and user privacy in web development and system administration.
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    This article provides a detailed guide on creating and configuring self-signed SSL certificates in Linux using Bash. It covers why self-signed certificates are beneficial for development and testing environments, and outlines essential steps including generating a private key, creating the SSL certificate with OpenSSL, and configuring web servers like Apache and Nginx to use these certificates. Practical command-line examples are provided to help users set up and secure their server communications.
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    The article discusses the use of the `` directive in Apache to improve server security by restricting HTTP methods like POST, PUT, and DELETE. By setting limits on these methods, administrators can prevent unauthorized actions and optimize server performance. It outlines how to implement these configurations using Bash, highlights common use cases, and suggests best practices for security enhancements in server setups.
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    The article examines the versatile roles of the hyphen "-" in Linux Bash, illustrating its use in command options, file handling, and data redirection. It explains how hyphens modify command behaviors, represent standard input/output in redirection, and act as placeholders in file descriptors and data streams. Examples and a Bash script highlight its practical applications in enhancing command functionality and script efficiency in Linux.
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    This blog post explores the Shellshock vulnerability (CVE-2014-6271) in Bash, used extensively in Unix-based systems. It demonstrates how attackers can execute arbitrary commands via Bash's environment variables and provides a script for safe, controlled exploitation. The article emphasizes the importance of updating Bash for security.
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    The article explores using Bash co-processes and netcat (nc) to set up a real-time, bidirectional chat system. It details how co-processes facilitate asynchronous command execution that interacts seamlessly with the main script. By using `nc`, it explains setting up connection points for the chat, and employing the `coproc` command to manage simultaneous message exchanges effectively, enhancing scripting capabilities in Linux.
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    The blog article describes using the Bash command `yes | tr \n x` to generate an infinite string until memory overload. It breaks down the `yes` command which repetitively outputs 'y', and the `tr` command which replaces newlines with 'x', forming a continuous 'yx' output. It emphasizes understanding the impact on system resources and includes a sample script for safely demonstrating the command without crashing the system.
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    The blog delves into controlling GPIO pins in Linux via the `sysfs` interface, explaining its use in user space for simple file operations on pins. Steps covered include exporting the pin, setting its direction, and manipulating its state. The guide includes examples like LED control and a script for blinking an LED, highlighting the ease and effectiveness of `sysfs` for basic hardware interfacing.
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    This blog article explains how to intentionally trigger a segmentation fault in Bash to test signal handling capabilities. It details creating a simple C program that accesses forbidden memory to cause a segfault, which is then compiled and executed from a Bash script. The script uses `trap` to manage the `SIGSEGV` signal, illustrating how to handle errors gracefully and improve software robustness by using Bash in conjunction with lower-level operations.
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    The blog post explores the `FUNCNAME` array in Bash, highlighting its importance in debugging by tracing function call sequences. It shows how `FUNCNAME` aids in understanding script execution paths and function hierarchies, enhancing script management and error diagnosis for both novice and experienced scripters. Various examples demonstrate its practical applications in real-world scripting scenarios.
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    The blog explores Bash's `compopt` builtin which allows dynamic modification of autocomplete options on the command line. By detailing features that enable the tailoring of behaviors, such as limiting file completions to `.txt` files and controlling spaces after completions, `compopt` is shown to significantly enhance user efficiency. Examples and script implementation advice offer practical insights for power users and system administrators.
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    The article explains side effects in Bash arithmetic expressions, particularly how pre-increment (`++i`) and post-increment (`i++`) operators affect a variable's value and the outcome of expressions. It highlights the importance of understanding these effects for efficient script writing in Bash, offering a detailed example and a script to demonstrate these concepts in action.
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    In Bash scripting, memory allocation plays a crucial role in script performance and reliability. Normally, Bash uses `mmap()` for large memory blocks, but it can be configured to use `malloc()`, which helps reduce virtual memory fragmentation and may enhance performance on some systems. Setting the `MALLOC_MMAP_THRESHOLD_` environment variable to 0 directs `malloc()` to never utilize `mmap()` for memory allocation. This adjustment is demonstrated through a sample script that showcases memory allocation in varied operations.
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    The article delves into advanced Bash debugging with `shopt -s extdebug` and `declare -ft`, tools that enhance script debugging by enabling detailed function tracing and execution flow tracking. It includes practical examples showing how these tools help in troubleshooting and improving script performance, making them indispensable for Bash developers.
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    The article details how to use `bash` scripts for real-time monitoring of `sudo` command usage by parsing the `/var/log/secure` file on Linux. It highlights the use of `tail` and `awk` to dynamically track and respond to `sudo` invocations, enhancing security and user accountability. A sample script is provided to demonstrate instant notification of `sudo` activities.
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    Discover how to create a basic port scanner using Linux's `/dev/tcp` and the `timeout` command in this blog post. The `/dev/tcp` pseudo-device facilitates direct TCP socket interactions from the Bash shell, enabling users to assess port availability. The post showcases how to manage connection timeouts with the `timeout` command to make scanning efficient and provides a script that demonstrates detecting open ports on specified host and port range.
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    This article details how to generate a Time-based One-Time Password (TOTP) token using Bash, `openssl`, and `date +%s`. It clarifies TOTP's role in two-factor authentication by combining a secret key and the current time to produce a constantly updating password. Step-by-step, the article demonstrates creating a TOTP token with a Bash script and accentuates the importance of secure key management.
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    This blog explores using `iconv` for transliterating accented characters to ASCII in Linux Bash, focusing on text processing pipelines. `iconv` converts text to various encodings, simplifying tasks like sorting or searching in ASCII-only systems. Examples include transliterating French text in the terminal or via scripts, enhancing text compatibility and handling diversity in characters and languages.
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Linux is a versatile, open-source operating system that is free and available for modification and redistribution under the GPL. It powers everything from cars to supercomputers, offering a secure, reliable platform for both new and seasoned users. Installation is straightforward, and software installation is simplified by integrated app stores or command-line tools.
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Discover how to explore the contents of Linux software packages without installing them. This insightful guide for developers and tech experts details methods using popular package managers like `apt`, `dnf`, and `zypper`. Learn to download and unpack `.deb` and `.rpm` packages to inspect contents, ensuring security, custom installations, or gaining educational insights with tools like `dpkg-deb`, `rpm2cpio`, and `cpio`. Ideal for those conducting security audits or exploring software packages across different Linux distributions.
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Master the management of GPG keys for trusted repositories in Linux environments with this detailed blog post. Learn the best practices for adding, verifying, and maintaining GPG keys using package managers like `apt`, `dnf`, and `zypper`. Gain insight into the key handling methods for Debian, Ubuntu, Fedora, CentOS, and SUSE systems to enhance the security and reliability of your software installations.
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This article delves into the functions of `/mnt` and `/media` directories in Linux, explaining their roles as mount points for managing storage devices. The `/mnt` directory is utilized for temporary, manual mounts by system administrators, while `/media` is designed for automatic mounting of removable media like USB drives and external hard disks. Best practices in managing these directories to maintain an organized and efficient filesystem are also discussed.
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Learn how to manually install DEB packages on Debian-based Linux distributions using dpkg. This guide covers basic installation steps, fixing missing dependencies with APT, and converting DEB packages for other distributions using tools like 'alien'. Ideal for users needing specific software versions or managing cross-distribution compatibility. Further resources explore dpkg, APT vs APT-GET, and more.
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This article reviews three universal Linux packaging formats: Snap, Flatpak, and AppImage. It covers each format's development, key features, advantages, and disadvantages. Snap, developed by Canonical, offers auto-updates and strong security but is large due to dependencies. Flatpak ensures enhanced security with robust sandboxing and supports multiple distros independently. AppImage, known for simplicity, requires no installation but doesn't integrate into systems as smoothly. Ideal for developers and users, the guide clarifies choosing the best manager based on security, simplicity, or resource use.
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This article compares Snap and Flatpak, two popular Linux package managers that aim to simplify app installation and management. It reviews aspects like installation speed, resource usage, and security, providing insights on each system's pros and cons. Snap is noted for its broad adoption and strong isolation but has downsides in resource usage. Flatpak, on the other hand, highlights decentralization and efficient runtime library sharing, with some complexity in setup. The analysis helps users and developers choose the right system based on their needs.
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Mastering `.bashrc` and `.bash_profile` enhances shell efficiency and customization on Unix-like systems. `.bashrc` configures session-specific settings like aliases in non-login shells, while `.bash_profile` is used for login sessions to set environment variables and start necessary programs. The article provides best practices and editing tips for both, crucial for user productivity.
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This article delves into managing multiple Linux distributions on a single system through dual booting, virtualization, and containerization. It covers practical usage of dual boot setups to utilize full hardware capacities, virtualization with tools like VirtualBox for OS isolation, and container usage via Docker for minimal overhead. It also explores package managers `apt`, `dnf`, and `zypper` specific to different distributions, enhancing system management for development, testing, or educational purposes.
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Discover how to develop and deploy a Progressive Web App (PWA) using the Linux Bash environment with this detailed guide. Covering setup with Node.js and Express.js, the guide instructs on crafting both offline and online functionalities, creating service workers, setting up a manifest file, and testing your PWA with tools like Lighthouse. Deployment options including Google Firebase and Heroku are also explored, ensuring your PWA is ready for public use.
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This article provides an in-depth look at crucial Linux mount options like `ro`, `rw`, `noexec`, `nosuid`, and more, explaining their impact on system security and performance. It covers basic settings such as read-only and read-write, and explores security-focused options that prevent binary execution, block privileges, and restrict device file creation. Additionally, it discusses performance-enhancing options and mounting preferences, emphasizing their practical applications and significance for maintaining a secure, stable, and efficient system.
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Discover the benefits of AppImage for portable applications across Linux systems. This guide discusses AppImage, a universal software package format enhancing compatibility and simplifying distribution across Linux without installation or root permissions. Learn to download, execute, and run AppImages, and integrate them using tools like AppImageLauncher for a seamless Linux experience.
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Learn how to expand your Red Hat Enterprise Linux (RHEL)-based system's software library by enabling the Extra Packages for Enterprise Linux (EPEL) repository. Our guide offers step-by-step instructions on installing EPEL using `yum` or `dnf`, enhancing system capabilities by accessing a broader range of applications and tools not available in the default repositories.
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This blog post guides on efficiently uninstalling software from Linux using package managers like apt, DNF, and Zypper. It covers the removal of software, configuration files, and dependencies to enhance system performance and prevent conflicts. The post gives detailed step-by-step instructions for each package manager and includes resources for further reading on Linux system optimization.
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This guide explores `sshfs` for mounting remote filesystems over SSH in Linux. It covers the installation of `sshfs`, setting up a local mount point, and securely mounting and accessing remote files. Additional insights include properly unmounting filesystems, making mounts persistent, and optimizing performance using SSH keys and other `sshfs` options, with resources for further exploration. Ideal for efficient and secure remote file management.
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Learn to download files using `wget` and `curl` on Linux. The article covers installing these tools on various distributions like Debian, Fedora, and openSUSE, and provides detailed usage instructions. Master commands for background downloads, specifying paths, and resuming downloads with `wget`, alongside saving files with specific names and making silent downloads with `curl`. Perfect for developers and Linux enthusiasts looking to enhance their data transfer skills.
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Explore effective methods to resolve broken package dependencies in Linux using `apt`, `dnf`, and `zypper`. This guide provides step-by-step procedures tailored for Debian/Ubuntu, Fedora/Red Hat, and openSUSE systems, including updating package lists, upgrading systems, and employing specific commands like `--fix-broken install`. Additional resources for further understanding are also suggested.
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This comprehensive guide delves into the Bash shell's history feature, teaching users how to view, recall, search, and clear command history. It covers advanced topics like setting custom history files and sizes, ignoring duplicates, and adding timestamps, aiming to boost efficiency and effectiveness in using the command line. Perfect for users of all levels seeking to optimize their terminal sessions and script integrations.
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