mdunwrap

README

mdunwrap

Remove unnecessary line breaks from Markdown text, for readers prefer to let their Markdown viewer soft-wrap text.

Usage

mdunwrap [options] [file]

Arguments

• -in: Path to the input file, or - for stdin. Defaults to stdin.
• -out: Path to the output file, or - for stdout. Defaults to stdout.
• -in-place: Path to a file which is read, used as input, and replaced by the output. Cannot be combined with -in or -out.
• -force: Allow -out to overwrite an existing file. Without it, writing to a path that already exists is an error.
• -version: Print version and exit.
• -help: Print help and exit.

A single bare filename argument is equivalent to -in.

-in-place writes to a temporary file in the same directory and renames it over the original, so an interrupted run cannot leave a truncated document behind. The file's permissions are preserved.

Usage Examples

Unwrap a file to stdout:

$ mdunwrap notes.md
# Notes

This paragraph was hard-wrapped in the source and is now a single line.

Rewrite a file in place:

$ mdunwrap -in-place notes.md

Read from a pipe:

$ pbpaste | mdunwrap | pbcopy

Write to a new file, refusing to clobber it:

$ mdunwrap -in notes.md -out wrapped.md
$ mdunwrap -in notes.md -out wrapped.md
wrapped.md already exists; pass -force to overwrite it
$ mdunwrap -in notes.md -out wrapped.md -force

Installation

macOS via Homebrew

brew install cdzombak/oss/mdunwrap

Debian/Ubuntu and derivatives, via apt repository

Install my Debian repository if you haven't already:

sudo apt-get install ca-certificates curl gnupg
sudo install -m 0755 -d /etc/apt/keyrings
curl -fsSL https://dist.cdzombak.net/deb.key | sudo gpg --dearmor -o /etc/apt/keyrings/dist-cdzombak-net.gpg
sudo chmod 0644 /etc/apt/keyrings/dist-cdzombak-net.gpg
echo -e "deb [signed-by=/etc/apt/keyrings/dist-cdzombak-net.gpg] https://dist.cdzombak.net/deb/oss any oss\n" | sudo tee -a /etc/apt/sources.list.d/dist-cdzombak-net.list > /dev/null
sudo apt-get update

Then install mdunwrap via apt-get:

sudo apt-get install mdunwrap

From source

A working Go installation is required.

git clone https://github.com/cdzombak/mdunwrap.git
cd mdunwrap
go build -ldflags="-X main.version=$(./.version.sh)" -o /usr/local/bin/mdunwrap .

What it does

mdunwrap joins lines in:

• Wrapped paragraph text
• Wrapped list item text (keeping the marker and indentation)
• Wrapped text inside blockquotes (keeping the > prefix)
• Wrapped setext heading text, footnote bodies, and definition descriptions

It leaves exactly as-is:

• Headings, thematic breaks, and blank lines
• Separate list items, and nested lists
• Table rows, including the header and delimiter rows
• Fenced and indented code blocks, and multi-line code spans
• HTML blocks and comments
• YAML and TOML frontmatter
• Explicit hard breaks: a line ending in two spaces or a backslash
• $$ math blocks, :::note admonitions, and > [!NOTE] alerts

Blocks are located with goldmark, a CommonMark-compliant parser. The result is then rendered and compared against the input, and any join that would have changed the rendered output is discarded. Everything outside the joins is copied through byte for byte, and running mdunwrap twice produces the same result as running it once.

License

Apache 2.0; see LICENSE in this repo.

Author

Chris Dzombak

• dzombak.com
• github.com/cdzombak