Awesome

goman - the missing man page for Go binaries

Note: Find the latest version here: appliedgocode/goman.

goman logo

Almost all Go binaries come without any man page, even when properly installed through means like Homebrew.

goman substitutes the missing man page by the README file from the Go binary's sources.

goman first grabs the source path from the binary. Then it tries to locate the README file locally via the GOPATH. If this fails, it tries to fetch the README file from the binary's public repository.

For that last option, goman makes a couple of assumptions about the location, but at least with github and gitlab, those assumptions should be valid.

Featured on episode #51 of the Go Time podcast! (In the "Free Software Friday" section, at 1:02:35)

Demo

goman demo

Usage

goman <go binary file>

goman <go binary file> | less -R

(-R tells less to render ANSI color codes.)

Installation

Binaries

Homebrew

brew tap appliedgo/tools
brew install goman

Manual download

On the release pages, open the latest release and download the binary that matches your OS and architecture.

From the source

You need a Go toolchain installed.

go install github.com/appliedgocode/goman@latest

This downloads and installs goman to $(go env GOPATH)/bin (or $(go env GOBIN) if set).

Arch Linux

Using an AUR helper application, such as paru -S goman-git.

Shell Integration

goman can blend in with the standard man command.

Bash example (to be placed in ~/.bashrc):

man() { 
    if ! /usr/bin/man $1; then 
        goman $1 | less -R; 
    fi; 
}

Fish example:

function man
    /usr/bin/man $argv; or goman $argv[1] | less -R
end

Credits and Licenses

All code that is written by myself is governed by a 3-clause BSD license, see LICENSE.txt.

The which package is part of the which command that is licensed under the MIT license; see LICENSE.which.txt.

The code that extracts the source code path from a go binary is a part of the gorebuild tool that is published under the MIT license; See LICENSE.dwarf.go.txt.

The Markdown renderer is a fork of blackfriday with extra code for rendering Markdown to plain text with ANSI color codes. See LICENSE.blackfriday.txt and the copyright notice in ec1oud/blackfriday/ansi.go.

Limitations

In its current state, goman is little more than a proof of concept. Bugs certainly do exist, as well as functional shortcomings due to oversimplified design, such as:

goman assumes that the README file contains either Markdown text or plain text. I know of at least one README.md that contains HTML. goman does not treat such cases in any special way.
If a binary originates from a command subdirectory of a project, chances are that this subdirectory contains no extra README file. goman then tries to find the README file in the parent directories.
Some binaries contain an absolute path to their source code, and goman assumes that the GOPATH used at compile time is the part from the root to the first directory named /src/. If the GOPATH itself contains a /src/ directory (e.g., "export GOPATH=/home/user/src/go"), goman fails extracting the relative source code path.
goman's output may wrap character-wise instead of word-wise.
Path redirection to canonical paths (like, e.g. from "https://npf.io/gorram" to https://github.com/natefinch/gorram) are not handled right now.

Changelog

v0.2.3

Large update to implement a simpler and more reliable method of getting the readme path for binaries built with Module support.

TODOs:

Support vanity module paths
Determine semver tag, in order to fetch the readme version that matches with the compiled version

v0.2.2 (2021-04-23)

Add goreleaser.yml
Various fixes

v0.2.1 (2017-07-04)

Fix stripping prefix from absolute path on Windows (PR #5)

v0.2.0 (2017-07-03)

Add support for the PE file format (Windows). (Implements issue #3)

v0.1.3 (2017-06-28)

Change search strategy for README file to cover all possible cases. (Fixes issue #2)

v0.1.2 (2017-06-27)

Fix slice panic if URL path is shorter than "github.com" (issue #1)