Stories with Tag Filesystem

• The practical (Unix) problems with .cache and its friends

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  Posted: 2025-02-05 07:26:51

  Verbose tl;dr

  The blog post argues against using generic, top-level directories like .cache, .local, and .config for application caching and configuration in Unix-like systems. These directories quickly become cluttered, making it difficult to manage disk space, identify relevant files, and troubleshoot application issues. The author advocates for application developers to use XDG Base Directory Specification compliant paths within $HOME/.cache, $HOME/.local/share, and $HOME/.config, respectively, creating distinct subdirectories for each application. This structured approach improves organization, simplifies cleanup by application or user, and prevents naming conflicts. The lack of enforcement mechanisms for this specification and inconsistent adoption by applications are acknowledged as obstacles.

  Chris Siebenmann's blog post, "The practical (Unix) problems with .cache and its friends," delves into the multifaceted issues surrounding the use of dot directories, specifically those intended for caching, in user home directories on Unix-like systems. While the XDG Base Directory Specification aimed to standardize the location of such directories (like .cache, .config, and .local), thereby improving organization and predictability, the practical implementation has revealed several shortcomings that impact system administrators and users alike.

  Siebenmann primarily focuses on the challenges these directories present for system backups and administration. The decentralized nature of these dot directories means that significant amounts of data, often transient and rapidly changing cache information, are scattered across numerous user home directories. This poses a problem for backup strategies. Including these directories in backups leads to inflated backup sizes, consuming valuable storage space and increasing backup times. Excluding them entirely, however, risks losing user-specific application configurations and potentially disrupting workflows upon restoration. This leaves administrators in a difficult position, forcing them to choose between bloated backups and potentially incomplete restorations.

  Furthermore, the blog post highlights the difficulty in managing disk space consumption related to these dot directories. Caching directories, by their very design, can grow rapidly and unpredictably. While disk quotas can be employed to limit overall user disk usage, they don't offer granular control over specific directory sizes within the home directory. This makes it challenging to prevent runaway cache directories from consuming excessive disk space and potentially impacting system stability. Users may be unaware of the burgeoning size of these hidden directories, further complicating the issue.

  Another point of concern raised is the lack of clear guidelines for managing the lifecycle of cached data. The XDG specification doesn't dictate how or when applications should purge outdated or unnecessary cache files. This leads to situations where stale or irrelevant data persists indefinitely, consuming disk space without providing any benefit. The absence of a standardized mechanism for cache eviction leaves users and administrators with the burden of manually cleaning up these directories, a process that can be tedious, error-prone, and often overlooked.

  Finally, the blog post touches upon the inconsistent implementation and adoption of the XDG specification across different applications. While many modern applications adhere to the standard, legacy applications and those developed without awareness of the specification may continue to create their own idiosyncratic dot directories, further exacerbating the organizational and management challenges. This inconsistency undermines the very purpose of the standardization effort, perpetuating the problems the specification was intended to solve. In conclusion, while the XDG Base Directory Specification represents a step towards better organization of user data, its practical implementation introduces complexities related to backups, disk space management, and cache lifecycle control, presenting ongoing challenges for Unix system administrators.

  • unix
  • Linux
  • Filesystem
  • .cache
  • XDG Base Directory Specification
  • Temporary Files
  • Caching
  • Disk Space
  • system administration
  • Dotfiles
  • Hidden Files
  • file management
  • best practices

  Summary of Comments ( 41 )
  https://news.ycombinator.com/item?id=42945109

  Verbose tl;dr

  HN commenters largely agree that standardized cache directories are a good idea in principle but messy in practice. Several point out inconsistencies in how applications actually use $XDG_CACHE_HOME, leading to wasted space and difficulty managing caches. Some suggest tools like bcache could help, while others advocate for more granular control, like per-application cache directories or explicit opt-in/opt-out mechanisms. The lack of clear guidelines on cache eviction policies and the potential for sensitive data leakage are also highlighted as concerns. A few commenters mention that directories starting with a dot (.) are annoying for interactive shell users.

  The Hacker News post "The practical (Unix) problems with .cache and its friends" (https://news.ycombinator.com/item?id=42945109) has generated several comments discussing the merits and drawbacks of the XDG Base Directory Specification, particularly concerning the .cache directory.

  Several commenters agree with the author of the linked blog post that while the specification is well-intentioned, its implementation has created practical issues. One commenter points out the annoyance of having numerous hidden directories cluttering their home directory, making navigation and management more cumbersome. They argue for a simpler, less fragmented approach to storing application data.

  Another commenter echoes this sentiment, suggesting that the proliferation of these directories complicates tasks like backups and disk space analysis. They wish for a more consolidated approach, perhaps allowing applications to store cache data within their own installation directories, provided appropriate permissions are managed. This approach is countered by another user who highlights the security implications, stating that allowing applications write access to their installation directories could create vulnerabilities if those directories are shared by multiple users or if the application itself is compromised.

  The discussion also touches upon the inconsistent adoption of the standard across different applications. Some commenters note that many applications still create their own application-specific directories within the home directory, rendering the XDG specification somewhat ineffective. They suggest that stronger enforcement or clearer guidelines are needed for developers to adhere to the standard.

  One commenter offers a practical workaround by using symbolic links to relocate the .cache directory to a dedicated partition or directory, allowing them to manage cache data separately. Another user suggests employing a tool like trash-cli to easily purge the contents of these directories when necessary.

  Some users express skepticism about the overall benefit of the standard, questioning whether the complexity introduced outweighs the advantages. They argue that the original intent – separating different types of application data – hasn't been fully realized, leading to a situation where users are burdened with managing a multitude of hidden directories without significant practical gain.

  A few commenters suggest alternative solutions, such as utilizing a dedicated /var/cache directory for all applications or leveraging more advanced filesystem features for managing temporary data. The idea of having package managers automatically clean up cache directories associated with uninstalled applications is also raised.

  In essence, the comments reflect a mixed reaction to the XDG Base Directory Specification and its implementation. While acknowledging the theoretical benefits of separating application data, many commenters express frustration with the practical implications of the standard, particularly the proliferation of hidden directories and inconsistent adoption across applications. Several workarounds and alternative approaches are suggested, highlighting a desire for a simpler, more streamlined approach to managing application data on Unix-like systems.

• Shunpo: Minimalist bash tool to make directory navigation a little bit faster

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  Posted: 2025-01-27 00:14:53

  Verbose tl;dr

  Shunpo is a minimalist Bash tool designed to streamline directory navigation. It learns frequently visited directories and allows users to quickly jump to them using short, custom aliases. By storing these aliases and their corresponding paths in a simple text file, Shunpo avoids complex databases and remains lightweight and portable. It offers basic commands for adding, removing, listing, and navigating to saved locations, simplifying the process of moving between commonly accessed folders within the terminal.

  Shunpo, a minimalist bash tool designed to streamline and expedite directory navigation, addresses the common frustration of repeatedly typing lengthy cd commands. It leverages a simple but powerful concept: associating short, memorable nicknames with frequently accessed directories. These nicknames, stored in a plain text configuration file typically located at ~/.config/shunpo/shunpo.conf, are then used with the shunpo command to quickly jump to the corresponding directory.

  The configuration file employs a straightforward key-value pair structure, where each line defines a nickname and its associated absolute path. This allows users to create highly personalized shortcuts for directories deeply nested within their file system. For example, a user might map the nickname "docs" to /home/user/Documents/Projects/CurrentProject/Documentation, enabling them to navigate to that location with the simple command shunpo docs.

  Shunpo's minimalist design focuses on speed and efficiency, eschewing complex features in favor of rapid directory switching. The tool is written in pure bash script, ensuring compatibility across a wide range of systems without requiring external dependencies. This simplicity also contributes to its fast execution, making directory transitions nearly instantaneous. Furthermore, the plaintext configuration file promotes transparency and easy management of the stored directory mappings. Users can directly edit the file to add, modify, or remove nicknames as needed, without relying on a separate configuration interface.

  By offering a concise and efficient way to manage frequently accessed directories, Shunpo aims to improve productivity and reduce the time spent on repetitive navigation tasks. Its uncomplicated implementation and reliance on standard bash functionalities make it a lightweight and portable solution for users seeking a faster way to navigate their file systems.

  • bash
  • shell
  • cli
  • command-line
  • directory navigation
  • Navigation
  • Filesystem
  • productivity
  • Tool
  • utility
  • Minimalist
  • fast
  • Shunpo
  • autojump
  • z
  • cd
  • Linux
  • unix
  • macOS

  Summary of Comments ( 33 )
  https://news.ycombinator.com/item?id=42835798

  Verbose tl;dr

  Hacker News users discussed Shunpo's utility and potential drawbacks. Some found its core functionality—quickly jumping to frequently used directories—appealing, especially combined with tools like fzf. Others questioned its value proposition over existing solutions like autojump, z, or fasd, particularly given its reliance on find. Concerns were raised about performance in large directory trees and the security implications of executing arbitrary commands generated from find results. Some suggested improvements, including leveraging shell builtins for better performance and integrating more advanced selection mechanisms. The project's minimalism was both praised and criticized, with some appreciating its simplicity and others desiring more features like directory tracking or the ability to ignore certain paths.

  The Hacker News post about Shunpo, a minimalist bash tool for faster directory navigation, has generated a moderate amount of discussion with several interesting comments.

  Many users appreciate the simplicity and minimalist approach of Shunpo. One user highlighted how this tool focuses on a specific, narrow use case and executes it well, contrasting it with more complex solutions like Z. Another echoed this sentiment, praising the tool's laser focus and expressing a preference for such single-purpose tools over larger, more feature-rich options. The lean nature of the script was also commended, with a user pointing out its small size and readability, making it easy to understand and modify if needed.

  Several users discussed alternative tools and approaches to directory jumping. One comment mentioned 'autojump' and 'z.lua', contrasting their predictive nature with Shunpo's explicit directory selection. Another user brought up 'cdp', highlighting its use of frecency and its ability to handle typos. The discussion also touched on the classic 'fasd' tool. These comparisons helped to contextualize Shunpo within the existing landscape of directory navigation tools, showing its distinct approach.

  The practicality of Shunpo was also a topic of discussion. One user questioned the necessity of such a tool, suggesting that using cd - or other shell built-ins might be sufficient for many use cases. This sparked a counter-argument that while basic navigation might be covered, Shunpo offers a quicker and more convenient way to jump between specific directories, especially when dealing with longer paths.

  A few comments delved into the technical aspects of Shunpo. One user suggested an improvement, recommending the use of push and popd instead of manipulating $OLDPWD directly for a potentially cleaner implementation. This comment spurred further discussion about the nuances of different shell commands and their behavior. Another user mentioned potential integration with the fuzzy finder 'fzf', which could enhance the directory selection process.

  Finally, the discussion touched upon the customization aspect. While appreciating the simplicity, a user suggested the possibility of adding an optional configuration file to allow users to tailor the tool to their specific needs and preferences.

  Overall, the comments reflect a positive reception to Shunpo. While some questioned its necessity compared to existing solutions, many praised its minimalist philosophy, ease of use, and potential for speeding up a common task. The discussion also explored alternative tools, technical improvements, and potential future enhancements, showcasing a thoughtful and engaged community response.

• The history and use of /etc./glob in early Unixes

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  Posted: 2025-01-13 05:44:29

  Verbose tl;dr

  /etc/glob was an early Unix mechanism (predating regular expressions) allowing users to create named patterns representing sets of filenames, simplifying command-line operations. These patterns, using globbing characters like * and ?, were stored in /etc/glob and could be referenced by name prefixed with g. While conceptually powerful, /etc/glob suffered from limited wildcard support and was eventually superseded by more powerful and flexible tools like shell globbing and regular expressions. Its existence offers a glimpse into the evolution of filename pattern matching and Unix's pursuit of concise yet powerful user interfaces.

  Chris Siebenmann's blog post, "The history and use of /etc/glob in early Unixes," delves into the historical context and functionality of the /etc/glob file, a mechanism for global command aliases present in Version 6 Unix and its predecessors. Siebenmann begins by highlighting the limited disk space and memory constraints of these early Unix systems, which necessitated creative solutions for managing common commands and reducing redundancy. /etc/glob addressed this by providing a centralized repository for text substitutions that would be applied system-wide.

  The post meticulously explains the operation of /etc/glob. Essentially, /etc/glob contained a list of pairs of strings. Whenever a command was entered, the shell would consult this file. If the first string of any pair matched the beginning of the command, the matching portion of the command would be replaced with the second string of that pair. This allowed for abbreviation of frequently used commands, parameterization of commands with common arguments, and even the creation of entirely new commands built upon existing ones.

  Siebenmann provides concrete examples gleaned from historical Unix sources, illustrating the practical application of /etc/glob. One example demonstrates how ls -l could be abbreviated to simply ll, significantly reducing typing effort. Another shows how commands could be pre-configured with specific options, such as always listing directories in long format. The post also emphasizes the powerful, albeit potentially confusing, ability to chain multiple substitutions together, allowing complex transformations of commands based on the defined patterns.

  The post further discusses the historical evolution of /etc/glob. While initially existing as a standalone file, its functionality was eventually incorporated directly into the shell itself in later Unix versions. This integration streamlined the command parsing process and obviated the need for a separate file. The reasons for this transition likely stemmed from efficiency improvements and a desire for a more unified command interpretation approach.

  Finally, Siebenmann draws a parallel between /etc/glob and modern features like shell aliases and functions. While functionally similar in their ability to create shortcuts and customized commands, /etc/glob differed in its global scope and its application prior to argument parsing. This distinction underlines the evolution of command processing in Unix systems, moving from a centralized, pre-parsing substitution mechanism to the more localized and flexible approaches prevalent today. The post concludes by noting the enduring influence of /etc/glob on contemporary features, serving as a historical precursor to the powerful command manipulation capabilities we take for granted in modern shells.

  • unix
  • History
  • Glob
  • Filesystem
  • etc/glob
  • Early Unix
  • File Matching
  • Pattern Matching
  • shell
  • Command Line
  • Ken Thompson
  • Dennis Ritchie
  • Unix V6
  • Unix V7
  • Operating Systems
  • Retrocomputing
  • unix utilities
  • /etc/glob
  • Globbing

  Summary of Comments ( 23 )
  https://news.ycombinator.com/item?id=42680437

  Verbose tl;dr

  HN commenters discuss the blog post's exploration of /etc/glob in early Unix. Several highlight the post's clarification of the mechanism's purpose, not as filename expansion (handled by the shell), but as a way to store user-specific command aliases predating aliases and shell functions. Some commenters share anecdotes about encountering this archaic feature, while others express fascination with this historical curiosity and the evolution of Unix. The overall sentiment is appreciation for the post's shedding light on a forgotten piece of Unix history and prompting reflection on how modern systems have evolved. Some debate the actual impact and usage prevalence of /etc/glob, with some suggesting it was likely rarely used even in early Unix.

  The Hacker News post titled "The history and use of /etc./glob in early Unixes" has generated a moderate discussion with several interesting comments. The comments primarily focus on historical context, technical details related to globbing, and personal anecdotes about using or encountering this somewhat obscure Unix feature.

  One commenter provides further historical context by mentioning that Version 6 Unix's shell did not support globbing, meaning the expansion of wildcard characters like * and ?, directly. Instead, /etc/glob was used as an external program to perform this expansion. This detail highlights the evolution of the shell and its built-in capabilities over time.

  Another commenter elaborates on the mechanics of how /etc/glob interacted with the shell. They explain that the shell would identify commands starting with an unescaped wildcard, then execute /etc/glob to expand the wildcards. The expanded argument list was then passed to the actual command being executed. This clarifies the role of /etc/glob as an intermediary for handling wildcards in older Unix systems.

  A subsequent comment thread discusses the use of set -f (or noglob) in modern shells to disable wildcard expansion. This connection is made to illustrate that while globbing is now integrated into the shell itself, mechanisms to disable it still exist, echoing the older behavior where globbing wasn't a default shell feature.

  Someone shares a personal anecdote about encountering remnants of /etc/glob in a much later version of Unix (4.3BSD). Although no longer functional, the presence of the /etc/glob file serves as a historical artifact, reminding users of earlier Unix implementations.

  Another comment explains the security implications of directly executing the output of programs in the shell. They highlight that directly substituting the output of /etc/glob into the command line could lead to command injection vulnerabilities if filenames contained special characters. This observation points to the potential risks associated with early implementations of globbing.

  A commenter also mentions the influence of Multics on early Unix, suggesting that some of these design choices might have been inherited or influenced by Multics' features. This provides a broader context by linking the development of Unix to its predecessors.

  Finally, a few comments touch upon alternative globbing mechanisms like the use of backticks, further enriching the discussion by presenting different approaches to handling filename expansion in older shells.

  Overall, the comments on the Hacker News post provide valuable insights into the historical context, technical details, and practical implications of /etc/glob in early Unix systems. They offer a glimpse into the evolution of the shell and its features, as well as the challenges and considerations faced by early Unix developers.