Explanation
The command apt-cache can be used to perform a full text search on all available packages on a Debian system. It searches the package names and the descriptions for an occurrence of the regular expression given as a keyword and prints out the package name and the short description1. The syntax is: apt-cache search keyword. For example, apt-cache search openssh will return a list of packages related to OpenSSH2. The other commands are not suitable for this task because:
* apt is a high-level command-line tool that provides a user-friendly way to manage packages, but it does not have a search option3.
* apt-get is a low-level command-line tool that handles the installation and removal of packages, but it does not have a search option4.
* apt-search is not a valid command.
* dpkg is a tool to install, build, remove and manage Debian packages, but it does not have a search option5. It can only list the installed packages with the option -l4. References:
* How To Search For Available Packages From Command Line In Debian, Ubuntu Or Linux Mint [APT]
- Linux Uprising Blog
* apt(8) - apt - Debian buster - Debian Manpages
* How to List Installed Packages on Debian | Linuxize
* Debian / Ubuntu Linux search package names with apt-cache command
* dpkg(1) - dpkg - Debian buster - Debian Manpages