Defining The Problem: Variable Values Lost Across Pipelines Bash pipelines allow commands to be chained together by connecting the standard output of one command to the standard input of another. This enables efficient data processing flows. However, pipelines also create subshells for each command. As a result, variables set in one part of a pipeline…
Finding Files Selectively with find The find command in Linux provides powerful capabilities for searching and selecting files based on a variety of attributes and metadata. With flexible options to match on names, sizes, modification times, permissions, and more, find enables precise targeting of subdirectories and files. The basic syntax of find is: find [starting…
Finding PDFs in Directory Trees The first step in recursively copying PDF files from directories is locating all the .pdf files that need to be copied. The Linux find command can be used to search directory structures and match file names ending in .pdf. For example, to find all PDFs under /home/user/documents and all subdirectories:…
What rsync Filters Allow You To Do The rsync utility allows you to efficiently transfer and synchronize files between locations. One of its most powerful features is the ability to selectively choose which files to copy or ignore during the transfer process. This is accomplished through versatile include and exclude filtering options. Rsync filters provide…
Lack of Software Compatibility One of the biggest obstacles for users looking to switch to the Linux desktop is the lack of compatibility with Windows software. Many users rely on commercial programs like Microsoft Office or the Adobe Creative Suite for work, and fear they won’t be able to run these programs on Linux. Running…
What is ZFS and How is it Different? The ZFS file system was developed by Sun Microsystems to provide improved data integrity, support for high storage capacities, and better performance. Key architectural features of ZFS include: Copy-on-write transactions – All modifications are done atomically to prevent corruption. Variable block size – Allocates data in optimal…
The Linux kernel forms the core of the Linux operating system. As an open-source project with worldwide collaborators, maintaining the security of the Linux kernel is critical. However, with over 30 million lines of code, the scale and complexity of the kernel also invite vulnerabilities. Both security researchers and attackers continuously probe the kernel for…
Preserving Command History Across Sessions Being able to preserve the bash command history between sessions and logins can be invaluable for auditing, debugging, and productivity. Here we explore some methods to export the current history to a file, import history files automatically during login, and configure seamless command history persistence in bash. Exporting the current…
Controlling Bash History Storage The Bash shell stores previously entered commands in a history list which allows you to access and reuse them. However, unchecked storage of command history can use up system resources and expose sensitive information. Fortunately, Bash provides configuration options to control how much history is saved and exclude sensitive commands. Setting…
Storing Unlimited Bash History The default Bash shell settings limit the amount of command history that is saved between sessions. Specifically, the HISTSIZE and HISTFILESIZE variables control the number of commands stored in memory during a session and written to the ~/.bash_history file when a session ends. The default values are 500 and 1000, respectively,…