The basic problem is that the terminal device driver doesn't consider a read to have happened until the user presses a return character - this means that no program is going to be able to read a single character unless they first tell the device driver: "Behave differently, and consider a read complete after a single character".

Hence the suggestion to use Term::ReadKey - it tells the device to behave differently. At a C level, you'd use tcsetattr out of the termios function set. If for some reason you don't think that your deployment environment will have Term::ReadKey installed, you could try a system call to stty; "stty cbreak" will enter the one-character-at-a-time mode and "stty icanon" will take you back. (see stty's man page)

By the way, on Win32 the way I'd approach this is though the InputChar function inside Win32::Console.

use Curses;
...#initialization stuff
my $char=getch();
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Another way is:

$buf = ' ';
while($buf) {
    sysread STDIN, $buf, 1;
    print "$buf\n" # or whatever else you want
            # to do with it ;)
}
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I've tested this out on linux and it works fine. Any reason why it wouldnt work on other platforms?

Editor: The problem with this method is that the sysread will hang until the user presses the RETURN key (so if the user really only enters one character and it isn't RETURN, then the program will just "hang").

Well, methinks we have demonstrated TIMTOWTDI quite well today ;)

Originally posted as a Categorized Answer.