8 Regular Expressions You Should Know

regex

http://net.tutsplus.com/tutorials/other/8-regular-expressions-you-should-know/

# insert a new line with '<null\>' as content every 6th line between lines 100 and 2000
100,2000s/\v(.*\n){6}/\0\<null\/\>\r/g
see http://stackoverflow.com/questions/10413906/how-to-add-a-line-after-every-few-lines-in-vim

# delete blank lines
:g/^$/d

# join all lines
:1,$join

# grep just ONE word
grep -ioh "\w*WORD\w*"