UNIX Tips

'VI' Search and Replace: -

Go to the Command Mode(By Pressing ‘Esc’)

First occurrence on current line: :s/OLD/NEW

On current line: :s/OLD/NEW/g

Between two lines #,#: :#,#s/OLD/NEW/g (example 1,10s/OLD/NEW/g)

Every occurrence in file: :%s/OLD/NEW/g

 To append the text at the end of  the line   

                     %s/$/ \>\> \/tmp\/test\/test.log/g  

Where

' \' - is a DELIMITER

Above command will add '>> /tmp/test/test.log' to end of the each line.

Eg, File having the line 

                    cat session.sql

                    ALTER SYSTEM KILL SESSION '358, 22' IMMEDIATE ; 

                    Would become

                    ALTER SYSTEM KILL SESSION '358, 22' IMMEDIATE ; >> /tmp/test/test.log  

To add the text infront of the line         

                    %s/^/SQL\> /

                    Would become

                    SQL> ALTER SYSTEM KILL SESSION '358, 22' IMMEDIATE ; >>  /tmp/test/test.log    

Remove ^M(Carriage Return) from the file:

You could face this issue when doing FTP/SFTP from Windows to Unix.

To remove ^M for say 100 files in a directory.

Just go the the directory  and run

                    perl -p -i -e 's/\r\n$/\n/g'   *

$  -  for the end 

 ^  -  for the beginning 

\  -  as a delimiter to special character (like > < $ etc) if putting special symbol..put "\" and then place the actual character you want to display. 

% - place after the command prompt to makes changes across the whole file.