GPS - Thu May 9, 2002: I use the following code in my file server to receive a password. It is quite nice, because it displays * for each entered character. It supports backspace, and when a control key is pressed it's ignored, instead of appending to the string. It uses the Unix Terminal Extension which is in the public domain. I place this code in the public domain too. Please feel free to extend this.
I'm just trying to pay back the Tcl community for all the help I've received. :^)
proc terminal:password:get {str} {
puts -nonewline $str
flush stdout
terminal:canonicalOff
terminal:echoOff
set chr ""
set inputStr ""
while 1 {
set chr [read stdin 1]
#Backspace
if {$chr == "\b"} {
if {[string length $inputStr] > 0} {
puts -nonewline "\x1b\[D"
puts -nonewline " "
puts -nonewline "\x1b\[1D"
set lastChar [expr {[string length $inputStr] - 2}]
set inputStr [string range $inputStr 0 $lastChar]
flush stdout
}
continue
}
#eat up escape characters
#example: ESCc ESC\[D ESC\[1D ESC\[11D
if {$chr == "\x1b"} {
set nextChar [read stdin 1]
if {$nextChar == "\["} {
#This isn't a simple 2 char escape sequence
#It could be ESC\[D or ESC\[= or ESC\[1D
set nextChar [read stdin 1]
if {[string is digit $nextChar] || $nextChar == "="} {
while 1 {
#eat up the digits
set nextChar [read stdin 1]
if {[string is digit $nextChar]} {
continue
} else {
#We read a char that wasn't a digit, so we are at the end.
#If the string we had was ESC\[22D we just read D
break
}
}
}
}
continue
}
flush stdout
if {$chr == "\n" || $chr == "\r"} {
break
}
append inputStr $chr
puts -nonewline *
flush stdout
}
terminal:canonicalOn
terminal:echoOn
#DEBUG
#puts "\n$inputStr"
if {[string length $inputStr] <= 0} {
return -code error "Please specify one or more characters for your password.\n"
}
return $inputStr
}