This is a tool for converting .schema file to .ldif file, in order to use cn=config backend instead of slapd.conf
It's easy to use:
  schema2ldif < myschema.schema > myschema.ldif

It was orignally written by OpenSides for FusionDirectory.
It's written in perl.

It follows these directions found in schema/openldap.ldif :

# This openldap.ldif file is provided as a demonstration of how to
# convert a *.schema file into *.ldif format. The key points:
#   In LDIF, a blank line terminates an entry. Blank lines in a *.schema
#     file should be replaced with a single '#' to turn them into
#     comments, or they should just be removed.
#   In addition to the actual schema directives, the file needs a small
#     header to make it a valid LDAP entry. This header must provide the
#     dn of the entry, the objectClass, and the cn, as shown here:
#
dn: cn=openldap,cn=schema,cn=config
objectClass: olcSchemaConfig
cn: openldap
#
# The schema directives need to be changed to LDAP Attributes.
#   First a basic string substitution can be done on each of the keywords:
#     objectIdentifier -> olcObjectIdentifier:
#     objectClass -> olcObjectClasses:
#     attributeType -> olcAttributeTypes:
#   Then leading whitespace must be fixed. The slapd.conf format allows
#     tabs or spaces to denote line continuation, while LDIF only allows
#     the space character.
#   Also slapd.conf preserves the continuation character, while LDIF strips
#     it out. So a single TAB/SPACE in slapd.conf must be replaced with
#     two SPACEs in LDIF, otherwise the continued text may get joined as
#     a single word.
#   The directives must be listed in a proper sequence:
#     All olcObjectIdentifiers must be first, so they may be referenced by
#        any following definitions.
#     All olcAttributeTypes must be next, so they may be referenced by any
#        following objectClass definitions.
#     All olcObjectClasses must be after the olcAttributeTypes.
#   And of course, any superior must occur before anything that inherits
#     from it.
