help2man を Homebrew, apk, apt, dnf, MacPorts, Nix, pacman, zypper でインストール

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• help2man

プロジェクトの歴史

help2man was written by Brendan O'Dea. The 1.021 README from April 2000 describes the tool as a script for creating simple man pages from help and version output, and the 1.022 NEWS entry in July 2000 says help2man became an official GNU program.

The GNU README explains the historical reason for the tool: much GNU documentation lived in Info format, while man pages remained expected in Unix environments. help2man provided a way to generate placeholder or useful man pages from the executable itself rather than maintaining a separate roff document by hand.

Over time the project added options for source/manual headers, localized manual pages, gettext support, Translation Project integration, GPLv3 licensing, reproducible-build date handling through `SOURCE_DATE_EPOCH`, and support for modern version-string patterns.

採用の歴史

help2man became common in GNU and distro build systems because it solved a mundane packaging requirement with little maintenance burden. It is packaged across Homebrew, Debian, Fedora, Arch, Alpine, MacPorts, Nix, and other systems, which matches its role as a build-time documentation utility rather than an end-user application.

Its adoption is strongly tied to Autotools-era release culture: generated tarballs often include man pages, while maintainers can derive them from command output during release preparation or packaging.

使われ方

The core command is `help2man [OPTION]... EXECUTABLE`; help2man runs the target program's help and version options, parses the output, and emits a manual page. Options customize the NAME paragraph, section, source, manual title, include snippets, locale, and the exact help/version flags.

The tool works best for commands whose `--help` output follows GNU-style conventions. For richer pages, maintainers add include files or post-process generated sections rather than writing the whole man page manually.

パッケージ好きにとっての重要性

help2man is a classic package-maintainer tool: it turns CLI self-description into a distro-friendly artifact. That makes it important in build recipes, release scripts, and reproducible packaging, even though users rarely invoke it directly after installation.

It also reflects a GNU documentation compromise. Texinfo may be the canonical manual format for many GNU tools, but package managers, lint tools, and Unix users still reward having a man page installed in the expected location.

タイムライン

• 2000: help2man 1.021 appeared on GNU FTP, and 1.022 became an official GNU program.
• 2001: Options were added for source/manual headers and nonstandard help/version flags.
• 2003: Localized manual-page support was added.
• 2009: The project updated to GPLv3 and expanded translation support.
• 2015: `SOURCE_DATE_EPOCH` support was added for reproducible generated pages.
• 2022: Version 1.49 documented continued maintenance of parsing, translation, and encoding behavior.

Related projects

• GNU Texinfo is the documentation ecosystem help2man complements.
• Autoconf, Automake, and other GNU build tools commonly coexist with help2man in release toolchains.
• Downstream package managers use help2man as a build-time dependency when upstream projects generate man pages.

ソース

• https://ftp.gnu.org/gnu/help2man/
• https://ftp.gnu.org/gnu/help2man/help2man-1.021.tar.gz
• https://ftp.gnu.org/gnu/help2man/help2man-1.49.3.tar.xz
• https://salsa.debian.org/bod/help2man
• https://www.gnu.org/software/help2man/