Resetting oracle xe system password

sudo su - oracle
if $ORACLE_SID not set
cat /etc/oratab
ps -ef | grep smon


. oraenv

enter XE for the ORACLE_SID and set ORACLE_HOME as install dir (look it up in /etc/init.d/oracle-xe)

then run

sqlplus / as sysdba
alter user system identified by newpassword;