Unix command for extracting lines befor and after a particular searched string pattern - unix

Question

How can I search for lines in a file and extract the lines above and below lines of the searched line .
My input is like
Tue Jun 26 14:59:46 2012
Warning ffffffff act_msg_ctms_remove_from_pending_queue: deleting message 44817201 from the queue.
Tue Jun 26 14:59:46 2012
Warning ffffffff Finishing processing record number 44817201
Tue Jun 26 14:59:46 2012
Warning 5000000 activity_queue_manager_finish_cb: unknown activity 120.
Tue Jun 26 14:59:46 2012
Warning ffffffff Activity State Machine priority (2) finished
Tue Jun 26 14:59:46 2012
Warning ffffffff
====================================================
Processing database file "INCOMING_MESSAGES" record number 47810234 from user "(unknown)"
Tue Jun 26 14:59:46 2012
Warning ffffffff ACTIVITY data: rec_num (47810234) size (116)
Tue Jun 26 14:59:46 2012
Warning ffffffff activity status: ACT_SENT
Tue Jun 26 14:59:46 2012
Warning ffffffff MESSAGE body "MVT
QFA6673/26.VHQOS.BNE
EA0541
"
Tue Jun 26 14:59:46 2012
Warning ffffffff Finishing processing record number 47810234
Tue Jun 26 14:59:46 2012
Warning ffffffff Activity State Machine priority (1) finished
Tue Jun 26 14:59:46 2012
Warning ffffffff
End processing record number 47810234
====================================================
And I require my output to be like
/
Tue Jun 26 14:59:46 2012
Warning ffffffff MESSAGE body "MVT
QFA6673/26.VHQOS.BNE
EA0541"
/
My search string would be MVT.
Pls help

Answer 1

For three lines before and after the match
grep -C 3 pattern filename
For more control on number of after and before lines to be displayed for a match, use
grep -A (num of after) -B (num of lines before) pattern filename
From man grep:
-A NUM, --after-context=NUM
Print NUM lines of trailing context after matching lines.
Places a line containing -- between contiguous groups of matches.
-a, --text
Process a binary file as if it were text;
this is equivalent to the --binary-files=text option.
-B NUM, --before-context=NUM
Print NUM lines of leading context before matching lines.
Places a line containing -- between contiguous groups of matches.
-C NUM, --context=NUM
Print NUM lines of output context.
Places a line containing -- between contiguous groups of matches.

Answer 2

Grep has options to display rows immediately before and after the match. The numbers in the command line below are the appropriate number of rows to display, after and before the match. E.g.
grep -A3 -B5 yoursearchpattern inputfilepattern
man grep is useful for details about the options.
Assuming you have GNU grep, to check you can use --version option:
> grep --version
GNU grep 2.6.3