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.
Summary of Comments ( 41 )
https://news.ycombinator.com/item?id=42945109
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 likebcachecould 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
.cachedirectory.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
.cachedirectory to a dedicated partition or directory, allowing them to manage cache data separately. Another user suggests employing a tool liketrash-clito 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/cachedirectory 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.