my $valid = qr/[\w\s]/;

while (<DATA>){
    # grab: ween{(commands)}
    if (/^ween\s*\{\s*($valid+;)\s*\}\s*$/) {
        my $cmd = $1;
        print "Found $cmd\n";
    }
    else {
        print "$0: Illegal chars or incorrect syntax!\n";
        print "Line: $_\n";
    }
}

__DATA__
ween { foo bar; }
ween { del *.*; }