From: kjana@...4lab.to (YANAGAWA Kazuhisa)
Date: 2002-08-28T19:36:22+09:00
Subject: Re: Stdin Password Reading

In message <200208272131.SAA41799@server.valenciene>
spectra@debian.org writes:

> How can I read a password from stdin without showing it (showing stars 
> instead, for instance)? I mean as a login program should do, or as passwd 
> does.

If I can assume you use a Unix like system and it supports termios
interface, then using termios module like this:

    # get current termios value of $stdin.
    orig = Termios.getattr($stdin)
    tios = orig.dup

    # make new value to be set by resetting ECHO and ICANON bit of
    # local modes: see termios(4).
    tios.c_lflag &= ~(Termios::ECHO|Termios::ICANON)

    # set new value of termios for $stdin.
    Termios.setattr($stdin, Termios::TCSANOW, tios)
    
    begin
      while c = $stdin.getc  # don't echoing and line buffering
        p c
      end
    ensure
      # restore original termios state.
      Termios::setattr($stdin, Termios::TCSANOW, orig)
    end

# You can use curses extension for this purpose but using it for tiny
# problem like this is not preferable.


Or, use extension library interfacing to getpass(3).... I don't
remember already that is, but believe writing such extension is not so
difficult.


-- 
kjana@dm4lab.to                                August 28, 2002
What can't be seen is what can't be there.