How can I enter a password using Perl and replace the characters with '*'?
https://stackoverflow.com/questions/701078
italiano
english
français
española
中国
日本の
العربية
Deutsch
한국어
Português
RussianQuestion
I have a Perl script that requires the user to enter a password. How can I echo only '*' in place of the character that the user types, as they type it?
I'm using Windows XP/Vista.
Solution
You can play with Term::ReadKey. Here is a very simple example, with some detection for backspace and delete key. I've tested it on Mac OS X 10.5 but according to the ReadKey manual it should work under Windows. The manual indicates that under Windows using non-blocking reads (ReadKey(-1)) will fail. That's why I'm using ReadKey(0) who's basically getc (more on getc in the libc manual).
#!/usr/bin/perl
use strict;
use warnings;
use Term::ReadKey;
my $key = 0;
my $password = "";
print "\nPlease input your password: ";
# Start reading the keys
ReadMode(4); #Disable the control keys
while(ord($key = ReadKey(0)) != 10)
# This will continue until the Enter key is pressed (decimal value of 10)
{
# For all value of ord($key) see http://www.asciitable.com/
if(ord($key) == 127 || ord($key) == 8) {
# DEL/Backspace was pressed
#1. Remove the last char from the password
chop($password);
#2 move the cursor back by one, print a blank character, move the cursor back by one
print "\b \b";
} elsif(ord($key) < 32) {
# Do nothing with these control characters
} else {
$password = $password.$key;
print "*(".ord($key).")";
}
}
ReadMode(0); #Reset the terminal once we are done
print "\n\nYour super secret password is: $password\n";
OTHER TIPS
In the past I have used IO::Prompt for this.
use IO::Prompt;
my $password = prompt('Password:', -e => '*');
print "$password\n";
If you don't want use any packages... Only for UNIX
system('stty','-echo');
chop($password=<STDIN>);
system('stty','echo');
You should take a look at either Term::ReadKey or Win32::Console. You can use those modules to read the single key strokes and emit '*' or whathever.
Building on Pierr-Luc's program, just added some control on the backslashes. With this, you can't keep pressing backslash forever:
sub passwordDisplay() {
my $password = "";
# Start reading the keys
ReadMode(4); #Disable the control keys
my $count = 0;
while(ord($key = ReadKey(0)) != 10) {
# This will continue until the Enter key is pressed (decimal value of 10)
# For all value of ord($key) see http://www.asciitable.com/
if(ord($key) == 127 || ord($key) == 8) {
# DEL/Backspace was pressed
if ($count > 0) {
$count--;
#1. Remove the last char from the password
chop($password);
#2 move the cursor back by one, print a blank character, move the cursor back by one
print "\b \b";
}
}
elsif(ord($key) >= 32) {
$count++;
$password = $password.$key;
print "*";
}
}
ReadMode(0); #Reset the terminal once we are done
return $password;
}
using Pierr-Luc's program
# Start reading the keys
ReadMode(4); #Disable the control keys
while(ord($key = ReadKey(0)) != '13' )
# This will continue until the Enter key is pressed (decimal value of 10)
{
# For all value of ord($key) see http://www.asciitable.com/
if(ord($key) == 127 || ord($key) == 8 && (length($password) > 0)) {
# DEL/Backspace was pressed
#1. Remove the last char from the password
chop($password);
#2 move the cursor back by one, print a blank character, move the cursor back by one
print "\b \b";
} elsif(ord($key) > 32) {
$password = $password.$key;
print "*";
}
}
ReadMode(0); #Reset the terminal once we are done
Have you tried storing the string (so that your program can still read it) and find out its length then create a string of the same length, but only use '*'?
