Shell（11）——awk（1）

Awk can process files by column, not only by rows like sed.
Format: awk parameter'action' The file to be processed
(1) The

first and fourth columns of the print column are printed out, and we can not Print and splice in order:

(2) Print the line number.
We can use the built-in parameter NR
<1> to be used in {}


ps: $0 means to display the content of all lines
<2> to be used outside {}