ip as-path access-list 1 deny _1234$
ip as-path access-list 1 deny _5678$
ip as-path access-list 1 permit .*

router bgp 100
neighbor 192.168.0.1 remote-as 200
neighbor 192.168.0.1 des ebgp-test
neighbor 192.168.0.1 filter-list 1 in

Juniper way:

protocols {
bgp {
group “ebgp-test” {
type external;
import test-in;
peer-as 200;
neighbor 192.168.0.1 {
}
}
policy-options {
policy-statement test {
from as-path [test test1];
then reject;
}
set policy-options as-path a “.*1234″
set policy-options as-path b “.*5678″
}