bash

All posts tagged bash by Linux Bash
  • Posted on
    Featured Image
    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.
    Open article
  • Posted on
    Featured Image
    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.
    Open article
  • Posted on
    Featured Image
    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.
    Open article
  • Posted on
    Featured Image
    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.
    Open article
  • Posted on
    Featured Image
    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.
    Open article
  • Posted on
    Featured Image
    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.
    Open article
  • Posted on
    Featured Image
    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.
    Open article
  • Posted on
    Featured Image
    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.
    Open article
  • Posted on
    Featured Image
    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.
    Open article
  • Posted on
    Featured Image
    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.
    Open article
  • Posted on
    Featured Image
    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.
    Open article
  • Posted on
    Featured Image
    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.
    Open article
  • Posted on
    Featured Image
    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.
    Open article
  • Posted on
    Featured Image
    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.
    Open article
  • Posted on
    Featured Image
    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.
    Open article
  • Posted on
    Featured Image
    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.
    Open article
  • Posted on
    Featured Image
    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.
    Open article
  • Posted on
    Featured Image
    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.
    Open article
  • Posted on
    Featured Image
    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.
    Open article
  • Posted on
    Featured Image
    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.
    Open article
  • Posted on
    Featured Image
    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.
    Open article
  • Posted on
    Featured Image
    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.
    Open article
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.
Open article
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.
Open article
The article explores the GPL, MIT, and Apache licenses in open-source software. GPL ensures software freedom by mandating the same license for derivatives. MIT offers extensive freedom, including commercial use, without requiring openness in derivatives. Apache is permissive like MIT but adds protection for patent rights. Understanding these licenses aids developers in selecting one aligned with their goals, such as control, freedom, or legal safety.
Open article
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.
Open article
This guide delves into mastering Bash completions, showcasing how to enhance command-line efficiency by writing and customizing bash completion scripts. It covers the basics, installation on various Linux distributions, and steps for enabling the feature. The article also provides a detailed tutorial on script creation, installation, and debugging, ideal for both novice and advanced users looking to improve their terminal operations.
Open article
Encountering the "Address already in use" error in Linux indicates a port conflict where another application is using a desired port. Resolve this by identifying the conflicting process using commands like `lsof`, `netstat`, or `ss`. Options to manage the issue include terminating the process, changing your application's port, or using dynamic port allocation. Prevent future conflicts with good documentation and dynamic service discovery.
Open article
Learn how to manually control package updates on Linux systems by disabling automatic upgrades. This guide provides instructions for managing updates using APT, DNF, and Zypper across popular Linux distributions like Debian, Fedora, and openSUSE, ensuring that package upgrades do not disturb system performance or operations. Further resources are provided to help manage and secure systems manually.
Open article
The article discusses using the `auditd` service to monitor user command history in Linux for enhanced security and compliance. It details how `auditd` captures system calls and commands, providing audit trails crucial for forensic purposes. It describes setting up rules to log all user commands and provides examples for specific users and commands, including script demonstrations for implementing and reviewing `auditd` logs.
Open article
Exploring the diagnostics and resolution of 500 Internal Server Errors in Linux Bash, this article offers step-by-step troubleshooting tactics. Key steps include reviewing server logs, checking .htaccess files, debugging application code, verifying file permissions, and assessing server resource needs. Each step employs Linux Bash commands to effectively identify and solve the root causes of these errors, facilitating smoother server operation and application management.
Open article
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.
Open article
Enhance Linux repository security using `apt-secure`, a tool ensuring package integrity in Debian and Ubuntu. The guide explores its setup, including GPG checks and HTTPS configuration for `apt`, `DNF`, and `Zypper` across various systems. Importantly, it helps users manage repository keys and maintain robust security measures, ensuring protection from unauthorized changes and maintaining a secure environment.
Open article
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.
Open article
This guide details how to manage orphaned packages on Linux systems using the `apt`, `dnf`, and `zypper` package managers, focusing on the removal of unused dependencies that clutter the system. Step-by-step instructions for identifying and deleting these packages are provided, alongside best practices to ensure system safety during cleanup. This is a valuable resource for users of Debian, Ubuntu, Fedora, and openSUSE aiming to optimize system performance.
Open article
Discover Ripgrep (rg), a modern search tool developed in Rust, enhancing file search efficiency in Linux systems. Ripgrep surpasses traditional tools like `grep` by obeying `.gitignore` rules, using advanced searching methods, and supporting multi-platforms. This guide details its installation using package managers like `apt`, `dnf`, and `zypper`, demonstrating its speed and ease of use.
Open article