Ldapsearch is available by default on most of Linux/Unix with Openldap packages installed.
else ldapsearch is also available on Windows servers: http://sourceforge.net/projects/openldapwindows/?source=directory
syntax: ldapsearch -x -LLL -E pr=200/noprompt -h [AD Host] -D [AD User] -w [AD Pass] -b [Base DN] -s sub "([LDAP Filter])" [attr list]
example: ldapsearch -b dc=mydomain,dc=net -h dc1.mydomain.net -D 'cn=app-nceldap,ou=services&applis,dc=mydomain,dc=net' -w passwd '(&(objectcategory=person)(objectclass=user)(employeeid=1234))' sAMAccountName