Common sqlplus commands

ACCEPT - Get input from the user 
DEFINE - Declare a variable (short: DEF) 
DESCRIBE - Lists the attributes of tables and other objects (short: DESC) 
EDIT - Places you in an editor so you can edit a SQL command (short: ED) 
EXIT or QUIT - Disconnect from the database and terminate SQL*Plus 
GET - Retrieves a SQL file and places it into the SQL buffer 
HOST - Issue an operating system command (short: !) 
LIST - Displays the last command executed/ command in the SQL buffer (short: L) 
PROMPT - Display a text string on the screen. Eg prompt Hello World!!! 
RUN - List and Run the command stored in the SQL buffer (short: /) 
SAVE - Saves command in the SQL buffer to a file. Eg "save x" will create a script file called x.sql 
SET - Modify the SQL*Plus environment eg. SET PAGESIZE 23 
SHOW - Show environment settings (short: SHO). Eg SHOW ALL, SHO PAGESIZE etc. 
SPOOL - Send output to a file. Eg "spool x" will save STDOUT to a file called x.lst 
START - Run a SQL script file (short: @)

source :

http://www.orafaq.com/wiki/SQL*Plus_FAQ

Oracle - Default Location for data files

To get the existing location

sql > show parameter db_create;

To set a new location

sql> alter system set db_create_file_dest='/home/ssinghal/oradata';

Vim - Reduce Backslashing

Appending a "\v" reduces the amount of backslashing the search expressions.

/codes\(\n\|\s\)*where : normal regexp
/\vcodes(\n|\s)*where  : very magic

source :
http://vim.wikia.com/wiki/Best_Vim_Tips

Vim - Open Current File in Explorer or Command Prompt

Put the following two lines in your vimrc files under window to get F11 and F12 to work as "command prompt here" and "explorer here" !

map  :silent !start cmd.exe /k pushd %:p:h
map  :silent !start explorer.exe %:p:h

source for tip1

"http://vim.wikia.com/wiki/Open_the_folder_containing_the_currently_open_file"

source for tip2

A variant of tip 1 using windows trick of adding a registry for folders to open a command prompt 

Note : % represents the file open in current buffer

Oracle dba_jobs : Breaking

exec dbms_job.broken(690,true);

where 690 is the job number obtained from
select * from dba_jobs

Oracle databases - startup and shutdown

Shutdown:

$ export ORACLE_SID=db_sid
$ sqlplus /nolog
sql> connect / as sysdba
sql> shutdown immediate

Startup :

$ export ORACLE_SID=db_sid
$ sqlplus /nolog
sql> connect / as sysdba
sql> startup mount
sql> alter database open;

Note: This needs to be done by logging on the machine where oracle database is installed