Combining -v flag and -A flag in grep

Question

I need to search a file for a string, remove any line that contains the string, and also remove the two lines following any line that contains the string. I was hoping I could accomplish this using something like this...

$ grep -v -A 2 two temp.txt
one
five
$

...but unfortunately this did not work. Is there a simple I can do this with grep or another shell command?

Answer 1

The following works both with GNU sed and with OS X.

$ sed '/two/{N;N;d;}' temp.txt
one
five

• find line matching two
• read in two more lines
• delete them

Answer 2

You can do this with awk, as per the following transcript:

pax> echo 'one
two
three
four
five' | awk '/two/ {skip=3} skip>0 {skip--;next} {print}'

one
five

It basically starts a counter of lines to throw away (3) whenever it finds the two string on a line. It then throws those lines away until the skip counter reaches zero. Any line that isn't marked for skipping is printed.

Answer 3

With GNU sed:

sed '/two/,+2d' temp.txt

This uses two-address syntax (addr1,addr2) to match lines with the word two (/two/) plus the two lines after (+2). The d command deletes those lines.