sqlplus is not coming up

I'm trying to upgrade 12.2 database to 19c

When i tried to startup the database from 19c home, sqlplus utility is not responding.

How do we fix this ! Error sqlplus is not coming up

[oracle@replica bin]$ pwd

/u01/app/oracle/product/19.3.0/dbhome_1/bin

[oracle@replica ~]$ export ORACLE_HOME=/u01/app/oracle/product/19.3.0/dbhome_1/

[oracle@replica ~]$ export PATH=/u01/app/oracle/product/19.3.0/dbhome_1/bin:$PATH

[oracle@replica ~]$ export ORACLE_SID=orclrep

[oracle@replica ~]$ sqlplus / as sysdba

[oracle@replica ~]$ sqlplus

[oracle@replica ~]$ sqlplus sys as sysdba

[oracle@replica ~]$ which sqlplus

/u01/app/oracle/product/19.3.0/dbhome_1/bin/sqlplus

[oracle@replica ~]$ sqlplus -v

Regards,