store password in korn

log(){
    typeset rundate=$(date +"%F %X")
printf "${rundate} -- $*\n"
printf "${rundate} -- $*\n" >> $screen_log
}

do_sql(){
sql=$*
out=$(sqlplus -s '/ as sysdba'<<-eof p=""> whenever sqlerror exit 1
whenever oserror exit 1
set heading off feedback off serveroutput on trimout on pagesize 0
$sql
EOF
)
ret=$?
printf '%s' "$out"
return $ret
}

store_pwd(){

load_env $destdb

log "checking database open mode..."
sql="select status from v\$instance;"
log "running sql: $sql"
out=$(do_sql "$sql")
ret=$?
[[ $ret -ne 0 ]] && { log "*** failed to query database -- \n$out"; exit 1; }
log "got: ${out}"
typeset local_inst_status=$out
[[ $local_inst_status != "OPEN" ]] && { log "*** $destdb is not OPEN, not able to store passwords; skipping"; return 102; }
sql=$(cat<<-eof p=""> set echo off
set lines 1000
col lines for a1000
select u.name ||','|| u.spare4 ||','|| u.password ||','|| du.default_tablespace ||','|| du.profile||','||u.defrole||','||du.authentication_type||','||'"'||u.ext_username||'"' lines
from user$ u join dba_users du on (u.name=du.username) where u.name in ('SYS','SYSTEM','ORA_NCYCLE') ;
EOF
)

log "querying password hashes..."
out=$(do_sql "$sql")
ret=$?
[[ $ret -ne 0 ]] && { log "*** failed to query database -- \n$out"; return 1; }

touch $pwd_store
chmod 600 $pwd_store
echo "$out" > $pwd_store
return $?

}
restore_pwd(){
# return 102: file hashes are not there->try with cloakware
# return 1: error

load_env $destdb
log "checking dump file at $pwd_store"

[[ ! -e $pwd_store ]] && { log "dump file with hashes does not exist"; return 102; }

cnt=$(grep -E "SYS|SYSTEM|ORA_NCYCLE" $pwd_store | wc -l)
[[ $cnt -ne 3 ]] && { log "dump file does not contain rows for SYS|SYSTEM|ORA_NCYCLE"; return 102;}

while read line 
do
usr=$(echo $line| awk -F, '{print $1}')
hash10g=$(echo $line| awk -F, '{print $3}')
hash11g=$(echo $line| awk -F, '{print $2}')

if [[ ! -z $hash11g ]];then
sql=$(cat<<-eof font="">
set feed on
alter user $usr identified by values '$hash11g;$hash10g';
EOF
)
elif [[ ! -z $hash10g ]];then 
sql=$(cat<<-eof font="">
set feed on
alter user $usr identified by values '$hash10g';
EOF
)
else 
log "password hash not found for user $usr"
return 102
fi

log "setting password for user $usr"
out=$(do_sql "$sql")
ret=$?
if [[ $ret -ne 0 && $out != *ORA-28007* ]]; then
log "*** failed to run sql -- \n$out"
return 1
elif [[ $ret -ne 0 && $out = *ORA-28007* ]]; then
log "password is already set"
else 
log "password set"
fi


done < $pwd_store

rm $pwd_store

return 0

}

dumping system, role and proxy grants for users

set long 10000000
      set longchunksize 1000000
      set pages 0 head off feed off echo off
      set lines 500
      col lines for a500 word_wrapped
      exec dbms_metadata.set_transform_param(dbms_metadata.SESSION_TRANSFORM,'SQLTERMINATOR',TRUE);
      select '-- SYSTEM GRANTS' from dual;
      select dbms_metadata.get_granted_ddl('SYSTEM_GRANT',du.username) as lines from dba_users du where du.username in (${preserve_grant_quoted}) and exists (select grantee from dba_sys_privs where grantee=du.username);
      select '-- ROLE GRANTS' from dual;
      select dbms_metadata.get_granted_ddl('ROLE_GRANT',du.username) as lines from dba_users du where du.username in (${preserve_grant_quoted}) and exists (select grantee from dba_role_privs where grantee=du.username);
      select '-- DEFAULT ROLES' from dual;
      select dbms_metadata.get_granted_ddl('DEFAULT_ROLE',du.username) as lines from dba_users du where du.username in (${preserve_grant_quoted}) ;
      select '-- PROXY GRANTS' from dual;
      select dbms_metadata.get_granted_ddl('PROXY', pu.client) as lines  from proxy_users pu where pu.client in (${preserve_grant_quoted}) ;

DDL locks

No way to specify DDL with wait option. It will always fail with "resource busy" error.
In 11g there's a way to do this, but before have to use brute force

declare
success boolean := false;
begin
while ( not success)
loop
begin
execute immediate 'alter table t1 drop column n5 ';
success := true;
exception
when others then
null;
dbms_lock.sleep(10);
end;
end loop;
end;


ref: