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

You want to do something very similar to the answer given

sed -n '
/page . of ./ { #when pattern matches
n #read the next line into the pattern space
x #exchange the pattern and hold space
d #skip the current contents of the pattern space (previous line)
}

x  #for each line, exchange the pattern and hold space
1d #skip the first line
p  #and print the contents of pattern space (previous line)

$ { #on the last line
x #exchange pattern and hold, pattern now contains last line read
p #and print that
}'

And as a single line

sed -n '/page . of ./{n;x;d;};x;1d;p;${x;p;}' 1.txt