ls -l $ORACLE_HOME/lib/libsqlplus.so Expected permissions: -rwxr-xr-x (755) or at least -rwxr--r-- (744). The owner should be the Oracle user (or a user in the dba group).
View current setting:
If it’s set to something exotic like JAPANESE_JAPAN.JA16EUC , verify that $ORACLE_HOME/nls/data contains the necessary data files. For testing, unset it: ls -l $ORACLE_HOME/lib/libsqlplus
echo $NLS_LANG Common working setting: AMERICAN_AMERICA.AL32UTF8 or AMERICAN_AMERICA.US7ASCII . ls -l $ORACLE_HOME/lib/libsqlplus