When we merged the changes in libimagrt so that it automatically detects
whether stdin/stdout is a TTY and provides the user with stderr in case
stdout is not a TTY, we forgot that things like
imag foo | grep bar
becomes impossible with that, because imag detects that stdout is not a
tty and automatically uses stderr for output.
But in this case, we don't want that. The output has to be stdout in
this case.
With this change, we have a flag in the runtime ("--pipe-magic" or "-P",
globally available) which turns on "pipe magic".
The expected behaviour is the following, if "-P" is passed:
* If stdout is a TTY, we print to stdout
* If stdout is not a TTY, we print to stderr
* If stdin is not a TTY, we do not provide it
If "-P" is not passed, we allow the user of libimagrt to use stdin for
interactive stuff (the interactive stuff is not yet implemented).
Signed-off-by: Matthias Beyer <mail@beyermatthias.de>
Matthias Beyer
ce0bd9298a