How do I copy everything from my terminal to a file including the stdout and the prompt using C?

Question

I know how to get the stdout into a file using dup/dup2 system calls, but how do I get the entire output that would be normally shown on my terminal(including the prompt that says my username along with the $ symbol and the current working directory) to a file?

Answer 1

Look up the script command in Unix systems. If you want to capture all keyboard and std in/out for a command, use the script executable. If you want to see how it's done, look up the source.

Answer 2

Can't comment cause of low reputation.

I would say there is no way to do that inside a code in C. Instead, you could use bash for example to redirect everything to a file, and leave the code in C as it is. In this way you have all the info you want to save: prompt, current directory, call to the program (including flags), and of course the output of the program.

Well, you can do:
-For bash prompt PS1: Echo expanded PS1 (in case you want it expanded, if not there is a simple way to do it just echong PS1)
- For executed command: https://unix.stackexchange.com/questions/169259/how-to-capture-command-line-input-into-logfile-and-execute-it-at-the-same-time
- Standard output and error output: Redirect stderr and stdout in a Bash script

And that's all you want to capture, I think.

Answer 3

Yes you can, but this may be difficult in many details (depending on your expert level). For the shell to behave normally (I would mean exactly as in a terminal), then it needs to interact with a terminal (special system object). So you need to create a program that behave like a terminal, this what pseudo-terminals devices (/dev) are intended for. Read documentation about this to implement it but roughly, your application should behave like the user so should be connected to the slave side of the pseudo-terminal, and the shell to the master side of the pseudo-terminal. Then you can easily log real inputs made by the user and catch outputs made by the shell.