ShellDoc

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Overview

ShellDoc is a tool for generating reStructuredText formatted documentation from shell scripts, or any programming language that uses the # symbol to denote comments. This generally makes it useful as a documentation generator for languages that do not have documentation generators.

While any language using # as a comment character can be used with ShellDoc, keep in mind that it is specifically tailored for shell scripting languages in the sh family.

ShellDoc is loosely inspired by the PowerShell documentation format, and is written in Python 3. ShellDoc has no dependencies beyond the Python 3 standard library.

Key Features

• Language-agnostic; ShellDoc does not attempt to parse or understand the documented source code at all - only lines that begin with # are even considered by ShellDoc.
• Standalone .rst output can be used with Sphinx, or with rst2pdf.
• Documentation syntax is human-readable, and every easy to learn.
• Stream-oriented, single-pass design make ShellDoc safe to use in pipelines.
  • HINT: use --input=/dev/stdin to accept input from pipes.

How to Document Scripts with ShellDoc

ShellDoc understands two types of documentation: documentation for scripts, and documentation for functions. Either or both can be present in a single input file. Documentation is broken into logical segments, which are further broken down into sections.

Script-level documentation begins with the following line (segment opening):

# .SCRIPTDOC

Function-level documentation begins with the following line (segment opening):

# .DOCUMENTS functionname

Both types of segments end with:

# .ENDOC

All commented lines in the input between a segment opening and it's associated .ENDOC constitute a segment.

Note that all leading whitespace to the # symbol, the #, and the first character after it are stripped. For example, consider this input:

# some text
#   some more text
#one more line of text

This would produce the output:

some text
  some more text
ne more line of text

Within a segment, there are a number of valid sections. Sections begin with a line of the format:

# .SECTION_TYPE

And end either at .ENDOC or when the next section begins.

The following section types are valid for script-level segments:

• .DESCRIPTION
• .SYNTAX
• .LICENSE
• .CHANGELOG
• .AUTHOR

The following section types are valid for function-level segments:

• .DESCRIPTION
• .SYNTAX

Aside from segment openings, .ENDOC statements, and section openings, all other lines of input that begin with # and are part of a segment/section are passed through unmodified (except for leading and trailing whitespace being stripped).

Note that empty commented lines are preserved, for example:

# some words
#
#
#

results in the output some words followed by 3 blank lines.

Runs of empty lines (containing only whitespace) imply a single blank line in the output. For example:

# paragraph 1
#
# paragraph 2

Would result in the output:

paragraph 1

paragraph 2

The .SYNTAX Section

All sections except for .SYNTAX are passed directly through to the output without modification, the Syntax section is a bit different. Namely, it is rendered as a reStructuredText pre-formatted code block (i.e. it is preceded by a ::, and each line in the Syntax section is indented by four spaces).

This design decision was made because there are many common plain-text styles and formats that do not translate well to reST.

ShellDoc Usage

usage: shelldoc [-h] --input INPUT [--output OUTPUT | --prefix PREFIX]
                [--doctitle DOCTITLE | --titledepth TITLEDEPTH] [--notoc]
                [--notitle]

A tool for documenting shell scripts

optional arguments:
  -h, --help            show this help message and exit
  --input INPUT, -i INPUT
                        Input file to process
  --output OUTPUT, -o OUTPUT
                        Output file for generated documentation, stdout by
                        default.
  --prefix PREFIX, -p PREFIX
                        Output file is written into this directory, and file
                        is named according to document title with / replaced
                        with _. This is specifically intended to be used in
                        conjunction with --titledepth for generating docs for
                        Sphix or similar.
  --doctitle DOCTITLE, -t DOCTITLE
                        Set document title, default is input filename
  --titledepth TITLEDEPTH, -d TITLEDEPTH
                        Set the document title to it's basename prefixed with
                        titledepth many parent directories (0 for basename
                        only)
  --notoc, -n           Do not include ..contents:: in output
  --notitle, -e         Do not include the document title in output

Examples

Please see the examples folder.

Roadmap

While ShellDoc is sufficiently complete to be useful, there are a number of features that could be added to improve it, some that come to mind include:

• Some better syntax to handle the functionality of .SYNTAX.
• Break out shelldoc into more modular components.
  • Add switches to extract individual segments and sections.
  • Build a library/API other Python code can use to extract individual segments and sections.
  • Add unit tests for each component.
• Add end-to-end smoke testing.

Contribution

Contributions in the form of suggestions, bug reports, documentation, and/or source code are gratefully accepted.

License

See the LICENSE file.