tcl pause & waiting for key pressed to continue

I'm looking for a way in tcl to pause the script (for example after some outputs with "puts") and wait for a key pressed from the user before continuing to output the remaining text.

With gratitude to Hai Vu's answer, if you're on a unix-like system with stty

proc anykey {{msg "Hit any key: "}} {
    set stty_settings [exec stty -g]
    exec stty raw -echo
    puts -nonewline $msg
    flush stdout
    read stdin 1
    exec stty $stty_settings
    puts ""
}
puts 1
anykey
puts 2

Link to thorough discussion on Tcl wiki: Reading a single character from the keyboard using Tcl