No they don't. Nor does passwd need a tty. You can run a script like this without any tty or user input.

#!/usr/bin/perl -w

use strict;
$|++;

my $HOME_DIR      = '/home/';
my $MAIL_DIR      = '/var/mail/';
my $CRAM_FILE     = '/etc/cram-md5.pwd';
my $USERADD_BIN   = '/usr/sbin/useradd';
my $PASSWD_BIN    = '/usr/bin/passwd';
my $PASSWD_FILE   = '/etc/passwd';
my $HTPASSWD_BIN  = '/usr/bin/htpasswd';
my $HTPASSWD_FILE = '/home/www/.htpasswd';

print "Username: ";
chomp(my $user = <>);
if(`grep /$user:/ $PASSWD_FILE`) {
    print "Username '$user' already exists! Continue (default=y) [y/n]
+: ";
    exit if <> =~ /n/i;
} 
else {
   `$USERADD_BIN "$user"`;
}

print "Shell Password: ";
chomp(my $shellpwd = <>);
if ($shellpwd) {
    open PWD, "|$PASSWD_BIN --stdin $user" or die "Can't open pipe to 
+$PASSWD_BIN $!\n";
    print PWD $shellpwd, "\n";
    close PWD;
}
else {
    print "No shell account password will be added!\n";
}

$shellpwd ||= 'password';
print "POP3 password (default='$shellpwd'): ";
chomp(my $pop3pwd = <>);
print "Shell and POP3 passwords will be the same!\n" unless $pop3pwd;
$pop3pwd ||= $shellpwd;
# avoid duplicate entries in cram-md5.pwd
open PWD, "<$CRAM_FILE" or die "Can't read $CRAM_FILE $!\n";
my @old_cram = grep { ! /$user\t/  } <PWD>;
close PWD;
print "Adding POP3 password to /etc/cram-md5.pwd\n";
open PWD, ">$CRAM_FILE" or die "Can't write $CRAM_FILE $!\n";
print PWD @old_cram,  "$user\t$pop3pwd\n";
close PWD;

print "Add to .htaccess (default=y) [y/n]: ";
unless ( <> =~ m/n/i ) {
    `$HTPASSWD_BIN -b $HTPASSWD_FILE $user "$pop3pwd"`;
}
[download]

cheers

tachyon

s&&rsenoyhcatreve&&&s&n.+t&"$'$`$\"$\&"&ee&&y&srve&&d&&print

You assume that all Unicies were created equal. That does not work on my Solaris 5.6 machine, whereas I assume that you're using some flavor of Linux judging by the GNU style '--stdin' parm.

thor