"Awk is a pattern-scanning and text processing utility that
captures information from text files creating reports in the
process, modify files from one format to another, create databases
and perform mathematical operations on data. The term "awk" comes
from the names of the authors, Aho, Weinberger and Kernighan. Nawk
is the newer version of awk and Gawk is the Gnu version. Often awk
is a symbolic link to gawk as you can see on this CentOS
GNU Awk 3.1.5
Copyright (C) 1989, 1991-2005 Free Software Foundation.
ls -l /bin/awk
lrwxrwxrwx 1 root root 4 May 22 07:43 /bin/awk -> gawk
"When awk is used data can be sent from standard input (stdin is
in put from the keyboard), files, or from output of another
process. When you engage awk it scans a file or the input, line by
line from the first line to the last searching for the lines that
match the criteria you have entered."