asciinema/asciinema

asciinema (aka asciinema CLI or asciinema recorder) is a command-line tool for recording and live streaming terminal sessions.

Unlike typical screen recording software, which records visual output of a screen into a heavyweight video files (.mp4, .mov), asciinema CLI runs inside a terminal, capturing terminal session output into a lightweight recording files in the asciicast format (.cast), or streaming it live to viewers in real-time.

The recordings can be replayed in a terminal, embedded on a web page with the asciinema player, or published to an asciinema server, such as asciinema.org, for further sharing. Live streams allow viewers to watch terminal sessions as they happen.

asciinema runs on GNU/Linux, macOS and FreeBSD.

Notable features:

• recording of terminal sessions to a file, with optional keyboard input capture and configurable environment variable capture,
• replaying of recordings inside a terminal, with adjustable speed, looping, idle time limiting, step-by-step navigation, pause-on-markers, and optional terminal auto-resize,
• local and remote live streaming of terminal sessions to multiple viewers in real-time, including a built-in HTTP server with an embedded web player for LAN/localhost viewing,
• combined sessions: record to a file while streaming locally and remotely at the same time,
• lightweight asciicast recording format, with native reading and writing of zstd-compressed (.zst) recordings (8% of the original size on average),
• conversion from asciicast v1/v2/v3 to asciicast v2/v3, raw terminal output, or plain text,
• concatenation of multiple recordings into one, with timing adjusted automatically,
• mid-session controls: pause/resume capture and add markers on the fly via customizable key bindings,
• session metadata capture, including terminal size, terminal theme, command, and title,
• configuration file support for defaults such as recording command, capture options, playback speed, idle time limit, notifications, and key bindings,
• headless mode, configurable terminal window size, and exit-status propagation for scripted and CI-friendly recording and streaming,
• support for stdin/stdout in conversion and playback from local files, stdin, or HTTP(S) URLs,
• integration with asciinema server, e.g. asciinema.org, for uploads, hosting, remote live streaming, self-hosted servers, visibility control, descriptions, and synchronized audio URLs.

To record a session run this command in your shell:

asciinema rec demo.cast

To stream a session via built-in HTTP server run:

asciinema stream -l

To stream a session via a relay (asciinema server) run:

asciinema stream -r

Check out the Getting started guide for installation and usage overview.

To download the source code, build the asciinema binary, and install it in $HOME/.cargo/bin in one go run:

cargo install --locked --git https://github.com/asciinema/asciinema

This requires the Rust toolchain (1.82 or later) with Cargo, installed via your system package manager or rustup.

Once installed, ensure $HOME/.cargo/bin is in your shell's $PATH.

Alternatively, you can build from a local checkout. First download the source code:

git clone https://github.com/asciinema/asciinema
cd asciinema

The recommended way to get the toolchain is the Nix dev shell, which provides everything needed and just works:

nix develop

If you don't use Nix, you need Rust with Cargo, as above.

Then build the binary with:

cargo build --release

This produces the binary at target/release/asciinema. You can just copy the binary to a directory in your $PATH.

To generate man pages and shell completion files, set ASCIINEMA_GEN_DIR to the path where these artifacts should be stored. For example:

ASCIINEMA_GEN_DIR=/foo cargo build --release

The above command will build the binary and place the man pages in /foo/man/, and the shell completion files in the /foo/completion/ directory.

All development happens on develop branch. This branch contains the current generation (3.x) of the asciinema CLI, written in Rust.

The previous generation (2.x), written in Python, can be found in the python branch.

For toolchain setup and build instructions, see Building. Run the test suite with cargo test.

If you'd like to propose or submit any changes, please read the contribution guidelines first.

Sustainability of asciinema development relies on donations and sponsorships.

If you like the project then consider becoming a supporter or a corporate sponsor.

asciinema is sponsored by:

• Brightbox

If you're interested in integration or customization of asciinema to suit your needs, check asciinema consulting services.

© 2011 Marcin Kulik.

All code is licensed under the GPL, v3 or later. See LICENSE file for details.