[GH-ISSUE #672] asciinema cat: functionality changed in v3.0.0 #956

New issue

Closed

opened 2026-03-15 11:07:02 +03:00 by kerem · 2 comments

kerem commented

2026-03-15 11:07:02 +03:00

Owner

Originally created by @4goettma on GitHub (Feb 4, 2025).
Original GitHub issue: https://github.com/asciinema/asciinema/issues/672

I've recently discovered that the functionality of 'asciinema cat' has been altered.
Arch Linux already updated its package repository to use the 3.0.0-rc.3 release candidate.

asciinema --help
cat Concatenate multiple recordings
in asciinema 3.0.0-rc.3

asciinema --help
cat Print full output of terminal sessions
in asciinema 2.4.0

What's the best way to recreate the former functionality? Using "asciinema play" with a very high value for the --speed parameter? (Neither an elegant solution as it plays the recording instead of printing it (less efficient) nor an exact replacement (for very long recordings))
Found a close solution:

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 ...

Is it still possible have asciinema output the recording to stdout instead of requiring an output file name?

I would be nice to keep backwards compatibility e.g. for scripting purposes and just name the new function differently ("concat"?)

Originally created by @4goettma on GitHub (Feb 4, 2025). Original GitHub issue: https://github.com/asciinema/asciinema/issues/672 I've recently discovered that the functionality of 'asciinema cat' has been altered. Arch Linux already updated [its package repository](https://archlinux.org/packages/extra/any/asciinema/) to use the 3.0.0-rc.3 release candidate. asciinema --help `cat Concatenate multiple recordings` in asciinema 3.0.0-rc.3 asciinema --help `cat Print full output of terminal sessions` in asciinema 2.4.0 ~~What's the best way to recreate the former functionality? Using "asciinema play" with a very high value for the --speed parameter? (Neither an elegant solution as it plays the recording instead of printing it (less efficient) nor an exact replacement (for very long recordings))~~ [Found a close solution](https://github.com/asciinema/asciinema/releases/tag/v3.0.0-rc.1): > `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 ...` Is it still possible have asciinema output the recording to stdout instead of requiring an output file name? I would be nice to keep backwards compatibility e.g. for scripting purposes and just name the new function differently ("concat"?)

kerem closed this issue

2026-03-15 11:07:07 +03:00

kerem commented

2026-03-15 11:07:13 +03:00

Author

Owner

@ku1ik commented on GitHub (Feb 4, 2025):

Sorry to hear it breaks your scripts... 😢

Is it still possible have asciinema output the recording to stdout instead of requiring an output file name?

You can do this:

asciinema convert demo.cast /dev/stdout -f raw

I think specifying stdout with a single dash would be nicer. That's something easy to implement. Will try to add that before the final 3.0.

I would be nice to keep backwards compatibility e.g. for scripting purposes and just name the new function differently ("concat"?)

3.0 is a major new release where we break backwards compatibility where it feels right. In the case of cat the original name was chosen inadequately (IMO), as cat is just a short for concat in UNIX parlance. Therefore the alterations, which I believe semantically fit better.

@ku1ik commented on GitHub (Feb 4, 2025): Sorry to hear it breaks your scripts... 😢 > Is it still possible have asciinema output the recording to stdout instead of requiring an output file name? You can do this: ```bash asciinema convert demo.cast /dev/stdout -f raw ``` I think specifying stdout with a single dash would be nicer. That's something easy to implement. Will try to add that before the final 3.0. > I would be nice to keep backwards compatibility e.g. for scripting purposes and just name the new function differently ("concat"?) 3.0 is a major new release where we break backwards compatibility where it feels right. In the case of `cat` the original name was chosen inadequately (IMO), as cat is just a short for concat in UNIX parlance. Therefore the alterations, which I believe semantically fit better.

kerem commented

2026-03-15 11:07:18 +03:00

Author

Owner

@ku1ik commented on GitHub (May 31, 2025):

With 3.0.0-rc.4 you can now do this:

asciinema convert demo.cast - -f raw

@ku1ik commented on GitHub (May 31, 2025): With 3.0.0-rc.4 you can now do this: ``` asciinema convert demo.cast - -f raw ```