How to grep the last occurrence of a line pattern

Question

I have a file with contents

x a x b x c 

I want to grep the last occurrence,

x c 

when I try

sed -n  "/x/,/b/p" file 

it lists all the lines, beginning x to c.

Answer 1

I'm not sure if I got your question right, so here are some shots in the dark:

• Print last occurence of x (regex):

  grep x file | tail -1 

• Alternatively:

  tac file | grep -m1 x 

• Print file from first matching line to end:

  awk '/x/{flag = 1}; flag' file 

• Print file from last matching line to end (prints all lines in case of no match):

  tac file | awk '!flag; /x/{flag = 1};' | tac