Shell Programming and Scripting

1-) first grep a word but the word u grep must appear at the end of the line (i know this part grep 'word'$)

2-) then You will filter your above grep results so
that you only consider matches on the evenly number lines

3-) Next, you will use ( sed 's_[^0-9].*__' ) to help you to locate the
middle line among all of these even numbered matches. ( this part is easy the program is already given)

4-) Your final result is that you will print this line

So: You end up with the median line among all even-numbered lines
that match to your word as the last word of its line & sentence.

Is this a homework assignment?

This should do the trick in one grep command

Code:

word="posted"
grep -E "^[^:]*[02468]:.*${word}$" yourfile.txt

But as Franklin52 stated, if this is part of an home assignment you should have posted it on the right forum Homework & Coursework Questions - The UNIX and Linux Forums

is an example question from internet reference book!