[skydhash]

There’s a function isatty that detect if a file descriptor (stdout is one) is associated with a terminal

https://man.openbsd.org/man3/ttyname.3

I believe most standard libraries has a version.

[sdsd]

I was about to comment the same thing. Usually I don't call the function directly, but via the tty command in my shell scripts:

  if tty -s; then
    echo "Standard input is a TTY (interactive mode)."
  else
    echo "Standard input is not a TTY (e.g., piped or redirected)."
  fi

Now I wonder how _isatty_ itself detects whether a file descriptor is associated with a terminal!

[skydhash]

In OpenBSD, with the fcntl system call

https://github.com/openbsd/src/blob/master/lib/libc/gen/isat...

https://man.openbsd.org/fcntl

https://github.com/openbsd/src/blob/master/sys/sys/fcntl.h

https://github.com/openbsd/src/blob/ba496e5267528b649ec87212...

https://github.com/openbsd/src/blob/ba496e5267528b649ec87212...