What is a .CAST file?
A .CAST file is a special type of file that captures everything that happens in a computer's terminal session. This means it records the text you type and the responses your computer gives, just like a video records images and sounds. However, instead of creating a traditional video, it saves this information in a way that can be played back in a terminal window. This is done using a program called asciinema, which is free for anyone to use.
The content inside a .CAST file is organized in a specific format. At the beginning of the file, there's a section formatted in JSON (a way to store information in an organized, easy-to-access manner) that includes details like when the recording started. Following this header, the file records all the text activity in the terminal, including what commands were typed and what results were shown, with timestamps to keep everything in order.
To view or play back a .CAST file, you can use the asciinema program itself. This allows you to see the terminal session exactly as it happened, in your own terminal window. If you want to share your terminal session with others, you can upload the .CAST file to the asciinema.org website, where anyone can watch it.
If you're curious about what's inside a .CAST file or need to make some changes, you can open it with any text editor, like Notepad on Windows, TextEdit on Mac, or Gedit on Linux. Since the file is essentially a text file with a specific structure, you can read the contents, but editing it might require some understanding of its format to avoid corrupting the playback.
In summary, .CAST files are a neat way to record and share terminal sessions, useful for tutorials, demonstrations, or debugging sessions. You can play them back with asciinema, share them online, or even peek inside with a simple text editor.
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