mdcat

mdcat [OPTIONS] [FILE]...

mdless [OPTIONS] [FILE]...

mdcat renders Markdown FILEs in CommonMark dialect to text terminals with sophisticated formatting. If no FILE is given, or if FILE is -, it reads from standard input.

CommonMark and terminal support

mdcat supports all basic CommonMark syntax plus a few extensions, highlights syntax in code blocks, and shows inline links and even inline images in some terminal emulators. In iTerm2 it also adds jump marks for section headings.

Pagination

mdcat can render output in a pager; this is the default when run as mdless. The environment variables $MDCAT_PAGER and $PAGER control the pager used.

Image support

In iTerm2, Kitty, Terminology and WezTerm mdcat prints inline images. mdcat supports most standard pixel formats by default.

mdcat silently ignores images larger than 100 MiB.

SVG support

In Terminology mdcat also renders SVG images, using the built-in support of Terminology.

In iTerm2, Kitty and WezTerm mdcat requires rsvg-convert to render SVG images to pixel graphics before displaying them; if rsvg-convert is not found in $PATH mdcat does not render SVG images in these terminals.

HTTP/HTTPS support

mdcat fetches images from HTTP(S) URLs for rendering if the underlying terminal supports image rendering; pass --local to disable this and force mdcat to only use images from the local filesystem. In this case remote images render as hyperlinks.

-p, --paginate

Paginate the output of mdcat with a pager like less.

Note: When paginating mdcat only uses basic ANSI formatting (no images, no hyperlinks) because pager programs normally do not support any sophisticated ANSI formatting features.

This is the default when run as mdless.

-P, --no-pager

Do not paginate output.

This is the default when run as mdcat.

-c, --no-colour

Disable all colours and other styles.

--columns

Maximum number of columns to use for text output. Defaults to the size of the underlying terminal.

-l, --local

Do not access remote resources.

--fail

Fail immediately at the first FILE which fails to read. By default mdcat continues with the next file.

-h, --help

Show a help message to the user and exit.

-V, --version

Show the version of mdcat and exit. The long flag also includes information about the builtin features.

mdcat exits with 0 if no error occurred, or 1 otherwise.

If run as mdless or if --paginate is given and the pager fails to start mdcat exists with 128.

TERM

If this variable is wezterm, mdcat assumes that the terminal is WezTerm. By default WezTerm does not set TERM to wezterm but mdcat can still detect it trough TERM_PROGRAM. If this variable is xterm-kitty, mdcat assumes that the terminal is Kitty. If this variable starts with foot, mdcat assumes that the terminal is foot.

TERM_PROGRAM

If this variable is iTerm.app, mdcat assumes that the terminal is iTerm2. If this variable is WezTerm, mdcat assumes that the terminal is WezTerm.

TERMINOLOGY

If this variable is 1, mdcat assumes that the terminal is Terminology.

VTE_VERSION

The version of a VTE-based terminal (such as Gnome Terminal).

The value of this variable contains four digits (e.g. 6201) which denote the major and minor version of VTE. If the value denotes a version greater than 5000 mdcat assumes that the terminal is a modern VTE terminal with support for hyperlinks. Otherwise mdcat treats the underlying terminal as plain ANSI terminal.

COLUMNS

The number of character columns on screen.

mdcat only uses this variable if it fails to query the size from the underlying terminal.

ROWS

The number of character rows on screen.

mdcat only uses this variable if it fails to query the size from the underlying terminal.

MDCAT_PAGER

The pager program to use for mdless or if --paginate is given.

The pager program must support basic ANSI formatting sequences, like e.g. less -R.

The value of this variable is subject to shell-like word-splitting. It is not subject to any kind of expansion or substitution (e.g. parameter expansion, process subsitution, etc.).

If set to an empty value, mdcat completely disables pagination.

PAGER

The pager program to use if $MDCAT_PAGER is unset.

Subject to the same rules as $MDCAT_PAGER.

If both $PAGER and $MDCAT_PAGER are unset use less -R as pager.

http_proxy, https_proxy, HTTPS_PROXY, all_proxy, ALL_PROXY

Proxies for HTTP, HTTPS, or both protocols, to use when fetching images.

Each variable provides the proxy for the corresponding protocol as URL, e.g. <http://proxy.example.com:3128>.

The lowercase name takes precedence; note that $http_proxy deliberately has no uppercase variant.

no_proxy, NO_PROXY

A comma-separated list of host/domain names or IP address not to use a proxy for.

Matches partial hostnames (e.g. example.org also disables proxy for www.example.org), but always at name boundaries.

CommonMark support and extensions

mdcat supports version 0.29 of the CommonMark Spec <https://spec.commonmark.org/>, plus Task lists <https://github.github.com/gfm/#task-list-items-extension-> and strikethrough <https://github.github.com/gfm/#strikethrough-extension->, through pulldown-cmark <https://github.com/raphlinus/pulldown-cmark>.

mdcat does not yet support footnotes and tables <https://github.github.com/gfm/#tables-extension->. mdcat parses HTML blocks and inline tags but does not apply special rendering; it prints HTML as is.

Terminal support

Unless --no-colour is given, mdcat translates CommonMark text into ANSI formatted text, with standard SGR formatting codes. It uses bold (SGR 1), italic (SGR 3) and strikethrough (SGR 9) formatting, and the standard 4-bit color sequences. It does not use 8-bit or 24-bit color sequences, though this may change in future releases.

Additionally mdcat uses OSC 8 <https://gist.github.com/egmontkob/eb114294efbcd5adb1944c9f3cb5feda> hyperlinks and other proprietary escape code if it detects specific terminal emulators:

·

iTerm2 <https://iterm2.com/>: OSC 8 hyperlinks, iTerm2 inline images <https://iterm2.com/documentation-images.html>, and Marks <https://iterm2.com/documentation-escape-codes.html>.

·

Kitty <https://github.com/kovidgoyal/kitty>: OSC 8 hyperlinks and Kitty Graphics <https://sw.kovidgoyal.net/kitty/graphics-protocol.html>.

·

Terminology <http://terminolo.gy>: OSC 8 hyperlinks and Terminology inline images.

·

VTE 3 based <https://wiki.gnome.org/Apps/Terminal/VTE> (0.50 or newer): OSC 8 hyperlinks.

·

WezTerm <https://wezfurlong.org/wezterm/>: OSC 8 hyperlinks and iTerm2 inline images.

·

foot <https://codeberg.org/dnkl/foot/>: OSC 8 hyperlinks.

Please report bugs to <https://github.com/lunaryorn/mdcat/issues>.

Currently mdcat does not yet wrap text to column limits, and does not provide means to customize styles and colours.

mdcat hello - world

Render markdown in hello, then from standard input, then from world.

mdless hello

Render markdown from mdless through a pager.

Copyright Sebastian Wiesner

and contributors

Binaries are subject to the terms of the Mozilla Public License, v. 2.0. See <https://github.com/lunaryorn/mdcat/blob/main/LICENSE>.

Most of the source is subject to the terms of the Mozilla Public License, v. 2.0, unless otherwise noted; some files are subject to the terms of the Apache 2.0 license, see <http://www.apache.org/licenses/LICENSE-2.0>.

cat(1), bat(1)

Sebastian Wiesner