While Debian did not originate dependency resolution in Linux, it was the first major distribution to develop it to modern standards. As early as 1994, Debian was using dpkg, a low-level front end for libapt-pkg that freed package installation from dependency hell – the seemingly endless effort to provide all necessary dependencies for a new package. Debian even took the problem one step further, adding suggested packages: Those that enhanced a package but were not strictly necessary for basic functionality. Although universal today, at the time dependency resolution was so unusual that other developers joked that Debian coders ordered lunch by typing apt-get sandwich. For ease of use, dpkg was soon supplemented by the even higher level apt-get command, although dpkg is still used for installation of local packages. Since those early days, apt-get has given rise to an entire ecosystem of utility scripts. In the past decade, the ecosystem became so complex that Ubuntu released apt, a simpler version of apt-get aimed at beginners or casual users. Today, Debian package management has become a comprehensive system that continues to evolve, but one whose intricacies can sometimes be overwhelming.

apt-get vs. apt

Like dpkg, apt-get and apt are both front ends for libapt-pkg and use the same lists of package repositories. Both have similar commands to install, remove packages, update repository lists, and remove packages that are no longer needed, although the command syntax is usually slightly shorter with apt (see Table 1). Both offer similar feedback. Although feedback is slightly cleaned up in apt, it is hard to tell one from the other (Figure 1). However, apt includes the functionality of apt-cache and apt-query, two widely used separate scripts for searching packages. In addition, apt displays the number of upgradeable packages and includes a progress bar, as well as the ability to edit lists of sources directly. However, apt-get has more options for upgrading and for solving installation problems. Moreover, not all apt-get-based scripts may be compatible with apt. In other words, apt is designed for the most common use cases and less knowledgeable users, while apt-get remains a choice for the more experienced. However, because both interact with the same library and resources, users can switch back and forth between them without any problems.

Repository Structure

Debian repositories are listed in /etc/apt, which also includes keyrings, preferences, and configuration files for apt-get and apt. Repositories can be edited in any text editor or directly with apt edit-sources, and the changes activated with apt-update. The entire system can be updated with apt-get dist-upgrade or apt full-grade update.

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