[Python-Dev] Incorrect documentation of the raw_input built-in function (original) (raw)

Guido van Rossum guido at python.org
Mon Jan 28 18:57:01 CET 2008

On Jan 28, 2008 12:35 AM, Greg Ewing <greg.ewing at canterbury.ac.nz> wrote:

Isaac Morland wrote:

> What about an option (maybe even a default) to send the prompt to stdin? > > The Postgres command line interface psql appears to do this: > > $ psql 2>&1 >/dev/null > Password: > $ No, it's probably using the C stdlib routine getpass(). From the man page: The getpass() function displays a prompt to, and reads in a password from, /dev/tty. If this file is not accessible, getpass() displays the prompt on the standard error output and reads from the standard input. So it appears that the official Unix Way prefers using stderr over stdout for prompting, if using the std files for it at all.

That's a dangerous generalization from just one example. I'd prefer it if you could unearth some POSIX or Linux base document saying this.

Writing to stdin would be wrong, since it's usually read-only, even when connected to a terminal.

Nowadays, it often is writable I've found, but we still shouldn't assume that.

-- --Guido van Rossum (home page: http://www.python.org/~guido/)

More information about the Python-Dev mailing list