asciinema/asciinema v3.0.0-rc.1 on GitHub

This is the first release candidate version of the brand new asciinema CLI 3.0.

It's a complete rewrite in Rust, bringing a lot of improvements and long requested features.

A major release is a good time for a cleanup, therefore some behaviours were changed and several things were dropped.

Live terminal streaming: asciinema stream -s (built-in HTTP server), asciinema stream -r (relay via asciinema server, e.g. asciinema.org)
Terminal theme capture for rec command - see theme entry in asciicast file
Recording to plain text file: asciinema rec foo.txt, asciinema rec foo.log --format txt
Format conversion: asciinema convert demo.cast demo.txt (to plain text), asciinema convert demo.cast demo.log --format raw (to raw output)
Short alias -a for --append for rec command
tmux status bar notifier - automatically enabled when tmux session detected
Support for system wide config file - /etc/asciinema/config.toml - see v3 config doc
--server-url global option, which overrides server URL set in the config file or via env var
--append option can now be used with raw output too (when --format raw used) in rec command
Info messages at the start and the end of the playback with the play command

asciinema rec always requires a filename now, doesn't offer uploading anymore (use upload command)
No more implicit asciinema server URL - new prompt for a server URL on first use (unless configured in the config file)
asciinema cat command concatenates multiple recordings into a new one in asciicast format, instead of dumping raw output (the previous functionality is now available via asciinema convert --format raw ...)
ASCIINEMA_API_URL env var changed to ASCIINEMA_SERVER_URL
New config file location (~/.config/asciinema/config.toml) and format (TOML) - see v3 config doc
Replaced --cols and --rows options with --tty-size in rec command
Replaced --raw option with --format raw in rec command
Renamed --stdin option to --input / -I in rec command

Better error message when non-UTF-8 locale is detected
Info messages at the start and the end of the recording session are now more clear
Use of --append and --overwrite options together with rec command returns error now
upload command verifies whether the file is a valid asciicast before uploading
Brought back saving of a custom record command (-c) in asciicast file header

Short version of the --env option in the rec command - -e - has been removed
--out-fmt and --stream options of the play command have been removed
Support for terminal-notifier has been removed