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

marks in vim - bookmarks

- Go to a line where you want a mark and press mx - this will create a bookmark

( x can be any alphabet from a-z)

- Now navigate away from that place. If you need to get back to the earlier cursor location press "`x" (back-tick and x)

- You can set multiple "marks" in a single file and navigate using back-tick and the alphabet used to create a mark

Cron entry for other users

Execute the following as root :

cat /var/spool/cron/ssinghal

where ssinghal is the user name

Sed - Deleting lines matching a pattern

sed -i '/.*log$/d' file_names.txt

Deletes all the lines ending with "log" from the file "file_names.txt"

marks in vim - bookmarks

Go to a line where you want a mark and press mx - this will create a bookmark

( x can be any alphabet from a-z)

- Now navigate away from that place. If you need to get back to the earlier cursor location press "`x" (back-tick and x)

- You can set multiple "marks" in a single file and navigate using back-tick and the alphabet used to create a mark

sed : inplace replacement

It is easy to open a file in vim and do a search replace - but if the file runs into huge sizes, a regular editor would not be able to perform search and replace tasks on it efficiently. For these situation, you need a "stream" editor. Here is an example for replacing "foo" with "bar" in a file called snafu.txt

sed -i -e 's/foo/bar/g' snafu.txt


Where:

-i : Is for inplace replacement

-e: sed script to be run on the file

samba mount

Using samba to mount a windows shared folder

mount -t cifs -o username=Home\\sandeep //192.168.0.1/Shared/ /media/Shared

Where /media/Shared is the target folder where the network folder will be mounted.