grep -NUM option
| grep -NUM is available not the -1 right | linux - What does `grep -1` do? - Super User : http://superuser.com/questions/1060709/what-does-grep-1-do | |
| grep -NUM not working correctly | grep - GNU Project - Free Software Foundation (FSF) : http://gnu.gds.tuwien.ac.at/software/grep/changes.html |