How to use the command 'debman' (with examples)

Debman is a highly useful command-line tool that allows users to read manual (man) pages from packages that are not yet installed on their system. This is particularly beneficial for users who want to access documentation without having to go through the installation process. By leveraging Debman’s ability to download and extract man pages directly from Debian package repositories or .deb files, users can efficiently gather information about software commands and functionalities prior to installation.

Use case 1: Reading a man page for a command that is provided by a specified package

Code:

debman -p package command

Motivation:

Imagine you are evaluating different software tools and want to understand their functionalities before installing them. Debman allows you to access the manual page of a command contained within a specified package directly from the package repository. This can help you decide whether the package meets your requirements without the need for installation.

Explanation:

• debman: The command to read man pages from potentially uninstalled packages.
• -p package: Specifies the package name from which to read the man page. Replace “package” with the actual name of the package.
• command: The specific command for which you want to access the man page. This is typically a command expected to be found inside the given package.

Example Output:

When executing the above command, the terminal will display the man page content for the specified command, detailing usage, options, and capabilities, exactly as it would if the package were installed locally.

Use case 2: Specifying a package version to download

Code:

debman -p package=version command

Motivation:

There might be situations where specific versions of a package have different features or options documented in their man pages. You could be interested in a particular version of a software package due to compatibility considerations or deprecated features. Debman allows you to specify the exact version of the package so that you can retrieve the relevant documentation.

Explanation:

• debman: Invokes the tool to fetch the desired man page.
• -p package=version: This specifies the exact package and version number you’re interested in. For instance, usage would look like -p nginx=1.18.0.
• command: The command for which you want to access the documentation at this specific version.

Example Output:

This command will produce the manual page for the specified command as found in the particular version of the package. This output will highlight version-specific features and options, which can be crucial for development and maintenance tasks.

Use case 3: Reading a man page in a .deb file

Code:

debman -f path/to/filename.deb command

Motivation:

There might be scenarios where you have downloaded a .deb file manually or received it from external sources, and you want to inspect its documentation without installing it. Debman allows you to directly read the man page from this .deb file, which is useful for offline analysis or verification before installation on your system.

Explanation:

• debman: Engages the utility to extract and read man pages.
• -f path/to/filename.deb: Specifies the path to the .deb file from which you want to extract the man page. Replace “path/to/filename.deb” with the actual file path.
• command: Indicates the command whose man page you want to retrieve from within the .deb file.

Example Output:

Upon running the command, you’ll see the extensive details of the command’s functionalities as found in the .deb package. It provides insights into what the command does, similar to a typical man page accessed directly on a system with the package installed.

Conclusion

Debman is an invaluable tool in scenarios where access to exhaustive software command documentation is needed without installing the software. By leveraging debman, users can make informed decisions about software utilities, understand the implications of specific versions, and validate downloaded .deb files, which enhances both efficiency and system security.