Export issue : UDE-00014: invalid value for parameter, 'attach'

Running expdp with sys as sysdba user:
============================

[oracle@RAC1 ~]$   /opt/oracle/product/11.2.0.3/db_1/bin/expdp \'/ as sysdba \'/ directory=expdp_22Nov14 dumpfile=expdp_22Nov14_LISTING_content_%U logfile=expdp_22Nov14_LISTING_content.log tables='EME.BMLS_LISTING' content=METADATA_ONLY exclude=constraint,ref_constraint,index,statisstatistics parallel=4

Export: Release 11.2.0.3.0 - Production on Mon Nov 24 01:45:54 2014

Copyright (c) 1982, 2011, Oracle and/or its affiliates.  All rights reserved.

Connected to: Oracle Database 11g Enterprise Edition Release 11.2.0.3.0 - 64bit Production
With the Partitioning, Automatic Storage Management, OLAP, Data Mining
and Real Application Testing options
UDE-00014: invalid value for parameter, 'attach'.

Correct Syntax:
==========


[oracle@RAC1 ~]$  /opt/oracle/product/11.2.0.3/db_1/bin/expdp  \'/ as sysdba\' directory=EXPDP_21NOV14 dumpfile=expdp_24Nov14_LISTING_content_%U content=METADATA_ONLY
 logfile=expdp_24Nov14_LISTING_content.log tables='EME.BMLS_LISTING' content=METADATA_ONLY exclude=constraint,ref_constraint,index,statisstatistics parallel=4


Export: Release 11.2.0.3.0 - Production on Mon Nov 24 01:56:51 2014

Copyright (c) 1982, 2011, Oracle and/or its affiliates.  All rights reserved.

Connected to: Oracle Database 11g Enterprise Edition Release 11.2.0.3.0 - 64bit Production
With the Partitioning, Automatic Storage Management, OLAP, Data Mining
and Real Application Testing options
Starting "SYS"."SYS_EXPORT_TABLE_01":  "/******** AS SYSDBA" directory=EXPDP_21NOV14 dumpfile=expdp_24Nov14_LISTING_content_%U content=METADATA_ONLY logfile=expdp_24Nov14_LISTING_content.log tables='EME.BMLS_LISTING'  content=METADATA_ONLY exclude=constraint,ref_constraint,index,statisstatistics parallel=4
Processing object type TABLE_EXPORT/TABLE/TABLE
Processing object type TABLE_EXPORT/TABLE/GRANT/OWNER_GRANT/OBJECT_GRANT
Processing object type TABLE_EXPORT/TABLE/TRIGGER
Processing object type TABLE_EXPORT/TABLE/STATISTICS/TABLE_STATISTICS
Master table "SYS"."SYS_EXPORT_TABLE_01" successfully loaded/unloaded
******************************************************************************
Dump file set for SYS.SYS_EXPORT_TABLE_01 is:
  /orabackup/expdp_21Nov14/expdp_24Nov14_LISTING_content_01.dmp
Job "SYS"."SYS_EXPORT_TABLE_01" successfully completed at 01:57:45


Also you can try:

expdp \"SYS@service AS SYSDBA\"