[solved] s/?eins/zwei/ gibt Fehler in Perl

perl -e '$_="eins";s/eins/zwei/;print "$_\n"'

perl -e '$_="?eins";s/?eins/zwei/;print "$_\n"'

Quantifier follows nothing in regex; marked by <-- HERE in m/? <-- HERE eins/ at -e line 1.

perl -e '$_="e?ins";s/e?ins/zwei/;print "$_\n"'

perl -e '$_="?eins";s/\?eins/?zwei/;print "$_\n"'

function stripWLANKeys() {

$PERL -e '

$mask="@@@@@@";
%keywords = ( "WIRELESS_KEY" => 1,              # SUSE -> /etc/sysconfig/network/ifcfg-*
             "WIRELESS_DEFAULT_KEY" => 1,
             "WIRELESS_KEY_0" =>1,
             "WIRELESS_KEY_1" =>1,
             "WIRELESS_KEY_2" =>1,
             "WIRELESS_KEY_3" =>1,
             "WIRELESS_KEY_LENGTH" =>1,
             "WIRELESS_WPA_IDENTITY" => 1,
             "WIRELESS_WPA_PASSWORD" => 1,
             "WIRELESS_WPA_PSK" => 1,
             "KEY" => 1,                        # RedHat -> /usr/share/doc/initscripts*/sysconfig.txt
             "wpa-psk" => 1,                    # Debian -> /etc/network/interfaces
             "wireless-key" => 1,
                                                # Arch ->
             "WLAN_KEY" => 1,                   # Slackware -> /etc/rc.d/rc.inet1.conf
             "WPAPSK" => 1,
        );


while (<>) {
        my ($key,$value) = /(\w+).*=.*['\''"](\S*)['\''"]/;
        if ($value) {
                if ( exists($keywords{$key})) {
                        s/$value/$mask/;
                }
        }
        print;
}' $1

perl -e '$_="?eins";s/\Q?eins\E/?zwei/;print "$_\n"'