Different output with ldapsearch

[Amos Castelli <amos.castelli@cscs.ch>]

Hi all,
can anybody tell me if the following is a bug or is a normal behavior?
$ ldapsearch -x -H ldap://ldap.ex.com -b ou=People,dc=ex,dc=com |grep zhiling
$ ldapsearch  -x -H ldap://ldap.ex.com -b ou=People,dc=ex,dc=com 
"(uid=zhiling)"

# extended LDIF
#
# LDAPv3
# base <ou=People,dc=ex,dc=com> with scope subtree
# filter: (uid=zhiling)
# requesting: ALL
#

# zhiling, People, ex.com
dn: uid=zhiling,ou=People,dc=ex,dc=com
uid: zhiling
cn: Uela Zhiling
objectClass: account
objectClass: posixAccount
objectClass: top
loginShell: /usr/local/bin/bash
uidNumber: 20893
gidNumber: 30484
homeDirectory: /users/zhiling
gecos: Uela Zhiling, DCS

# search result
search: 2
result: 0 Success

# numResponses: 2
# numEntries: 1


why I don't get any match with the grep command?
ldap server version: 2.3.34
Thanks in advance,
AMos