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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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 covers FAT32 and NTFS file system support in Linux, essential for users managing dual-boot systems or accessing Windows-formatted drives. It discusses the native compatibility and usage of FAT32, and the implementation of NTFS through NTFS-3G for reliable read and write functionality. It also provides practical guides on handling these file systems in Linux to maintain workflow efficiency across different operating environments.
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Learn to master rsync over SSH for secure and efficient data transfer and synchronization in Linux systems. This detailed guide offers insights into rsync's installation, key features like delta encoding, and secure usage practices. It serves as a foundation for system administrators and IT professionals to enhance their file management skills, complete with practical examples and tips for optimizing rsync operations in various Linux environments.
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Explore the comprehensive guide on Cargo, Rust's package manager. Learn how to install and configure Cargo across different Linux distributions using `apt`, `dnf`, and `zypper`. Understand key features like dependency management, project structure standardization, and extensibility with plugins. The guide also covers Cargo installation steps, including using Rustup, ensuring easy management of Rust projects.
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This article explains how to utilize `i2c-tools` for managing I2C devices on Linux systems. It begins with an introduction to the importance of `i2c-tools` for debugging I2C buses and devices, followed by installation guidelines across various Linux distributions. The piece details procedures for detecting I2C buses and devices, and demonstrates reading and writing to I2C devices using `i2cget` and `i2cset`. An example script is provided, illustrating how to read temperature from a sensor and configure a register, underscoring the tools' ease and efficiency for embedded system management.
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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 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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This article provides an in-depth explanation of Linux mount points, the directories where storage devices are accessible within the filesystem. Covering how to use mount commands, view mounted devices, and differentiate between temporary and permanent mounts through the `fstab` file, it's a vital resource for anyone looking to manage storage in Linux efficiently, highlighting organizational, security, and flexibility benefits.
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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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This guide provides an in-depth exploration of bind mounts in Linux, detailing their implementation at the kernel level, usage in scenarios like data migration and Docker containerization, and how to ensure their persistence using `/etc/fstab`. It also highlights essential security considerations to prevent unauthorized data access.
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Learn how to configure HTTP/3 with Apache, leveraging the new QUIC protocol for improved web performance. This guide covers the installation of Apache and the experimental mod_http3, adjustments for QUIC protocol support, and firewall settings for UDP traffic on port 443. Despite being challenging due to limited native support, adopting HTTP/3 can significantly better your site's reliability and speed.
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Learn how to configure RAID arrays in Linux, exploring various RAID levels from RAID 0 for performance to RAID 10 for speed and redundancy. This guide provides detailed, step-by-step instructions using mdadm for effective RAID setup and management, enhancing data redundancy and boosting system performance while offering tips on maintenance and monitoring. Ideal for both beginners and experienced Linux users.
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This article delves into the practice of package pinning in APT, a key tool in Debian and Ubuntu for prioritizing certain package versions during updates, ensuring system stability. Detailed steps for setting pin preferences in `/etc/apt/preferences` are provided, alongside comparisons with other package managers like DNF for Fedora and Zypper for openSUSE, highlighting their unique approaches to package prioritization.
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This comprehensive guide details effective methods for logging outputs from scripts in programming environments such as Bash, Python, and PowerShell. Learn the significance of logging for debugging, creating audit trails, and improving performance insights. The article highlights best practices like maintaining consistent log formats and securing log data, and explores external tools like Splunk and ELK Stack for advanced logging capabilities. Ideal for developers aiming to enhance scripting with robust logging practices.
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