Skip 1 field before sorting and stop after sorting the second field. Ignore leading blanks. In the case of identical fourth fields, sort by the first field. A word is a string of characters delimited by spaces, tabs, or newlines. If any options are used, just those counts appear.
Single quotes cause the shell to ignore what's inside and pass the pattern directly to grep .
Matches any character. Matches any character in string . Anchors to the beginning of the line. It is safest to enclude the entire pattern in single quotes ' ' . Allows more extensive pattern matching than grep .