This is a simple SQL statement to get you a list of all users and their roles in the Oracle DB:
“SELECT * FROM DBA_role_privs;”
And if you want to get the list of users related to a specific role, you can simply modify the SQL statement to be like this:
“SELECT * FROM DBA_role_privs where GRANTED_ROLE=’SSE_ROLE’;”
Source: http://www.dbforums.com/oracle/1650816-how-get-list-all-users-their-roles.html
This is one of the most important things to learn by any System Admin.; the CPU Load Average.
You can get the value simply by running the command “top” to get you the average value in the last 1 min, 5 min and 15 min.
How can you know whether that load average is high or not? That depends on the number of cores you have on your server, so for example, if you have 1 core, then a max. of load average value of 1 would be ok, although you should be a little concerned when it reaches about 0.7 (70%), if you have 2 cores, then 1.4 would be the max. accepted value …etc.
You can get to know the number of cores you have by the following command: “cat /proc/cpuinfo | grep “model name” | wc -l“, so for example if you have 8 cores, then a value of 5.6 (70%) is the max. accepted value, where you should start getting worried afterwards.
As a rule: “The “100% utilization” mark is 1.00 on a single-core system, 2.00, on a dual-core, 4.00 on a quad-core, etc.”, and you can start worrying above the 70% utilization.
Source: http://blog.scoutapp.com/articles/2009/07/31/understanding-load-averages
cat /proc/cpuinfo | grep “model name” | wc -l
example output: 24
This means that you have 24 cores on your server.
SQL> SELECT STARTUP_TIME FROM dba_hist_database_instance ORDER BY startup_time DESC;
STARTUP_TIME
—————————————————————————
29-SEP-13 03.43.07.000 AM
29-SEP-13 03.42.31.000 AM
29-SEP-13 03.12.45.000 AM
29-SEP-13 03.11.28.000 AM
28-SEP-13 11.56.35.000 PM
07-SEP-13 10.04.07.000 PM
6 rows selected.
Credit goes to Abdulrahman Galal from Oracle.
sed -i ‘s/old-test/new-text/g’ filename
This replaces the word old-test with the word new-text in the file named filename.
Just Some Techie Notes! 