Piping input from the shell behaves poorly

[kotfu]

(Cmd)
Documented commands (type help <topic>):
========================================
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stty: stdin isn't a terminal
(Cmd) stty: stdin isn't a terminal

Notice how the command is not output by Cmd2, but the prompt is. This means that the output can not be used as a transcript. There are several options to improve the behavior:

1. Output the prompt and the command. This makes the output a testable transcript.
2. Output neither the prompt or the command. This makes the output easily parseable by other command line utilities that may want to consume only the output. This is the current behavior of the load command, which does a similar thing.
3. Make some setting which allows you to choose between option 1 or option 2. Subclasses of Cmd2 could get this setting from a command line switch, or permanently set it one way or the other.

The other problem are the mysterious 'stty: stdin isn't a terminal' messages. A cursory glance at the code in _cmdloop seems to indicate that Cmd2 always expects to read input from a tty. When we run the load command, the commands to run get added to .cmdqueue and nothing is read from stdin.

[tleonhardt]

As far as the options go, I like either 2 or 3.

The echo setting may be the appropriate setting. If it is on, then the command name (but not prompt) will print out when using the load command for example. Now that I think about it, it would be better if the prompt printed as well.

Regarding the stty: stdin isn't a terminal messages, that only happens if you are using input direction at invocation of your cmd2 app.

Supposing the "help.txt" file contains just the text "help", if you do the following from the command-line:

./cmd2.py < help.txt

Then you will see the output with the mysterious messages.

However, if you do the following within a running cmd2 app's cmdlloop(), the stty messages will not appear:

(Cmd) < help.txt

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[tleonhardt]

Of possible relevance ... cmd2 and its cmd parent allow you to pass a stdin argument to the initializer. If this argument isn't None, then cmd uses it to set self.stdin, otherwise self.stdin gets set to sys.stdin.

[tleonhardt]

I committed a small change earlier which fixed the issue with the load command not printing the prompt when echo is set to True.

[kotfu]

I've created a new branch to start working on this. I agree the echo setting is the right one, so I'm gonna pursue option 3.