The question mark is displayed in SQLPLUS. in linux, the question mark is displayed in sqlplus, as shown below: [oracle @ why-server ~] $ Sqlplus/as sysdba SQL * Plus: Release 11.2.0.1.0 Production on Wed May 15 16:20:03 2013 Copyright (c) 1982,200 9, Oracle. All rights reserved .??? : Oracle Database 11g Enterprise Edition Release 11.2.0.1.0-64bit ProductionWith the Partitioning, OLAP, data Mining and Real Application Testing options SQL> shutdown immediate ;???????????????? ORACLE ??????? SQL> startupORACLE ??????? Total System Global Area 1.0689E + 10 bytesFixed Size 2216344 bytesVariable Size 5905583720 bytesDatabase Buffers 4764729344 bytesRedo Buffers 16945152 bytes ???????????????? Solution: [oracle @ why-server ~] $ Export NLS_LANG = american_america.zhs16gbk [oracle @ why-server ~] $ Vi ~ /. Bash_profile NLS_LANG = american_america.zhs16gbk; export NLS_LANG.