How do I delete a matching line and the previous one?

Question

I need delete a matching line and one previous to it. e.g In file below I need to remove lines 1 & 2.

I tried \"grep -v -B 1 \"page.of.\" 1.txt and I

Answer 1

Not too familiar with sed, but here's a perl expression to do the trick:

cat FILE | perl -e '@a = ;
                    for( $i=0 ; $i <= $#a ; $i++ ) { 
                     if($i > 0 && $a[$i] =~ /xxxx/) { 
                       $a[$i] = ""; 
                       $a[$i-1] = "";
                     }
                    } print @a;'

edit:

where "xxxx" is what you are trying to match.