#!/usr/bin/awk -f

# https://www.grymoire.com/Unix/Awk.html

# awk (named for its creators aho, weinberger and kernighan) takes a a text
# file as input.  the awk program then processes that file line by line.

# think of the awk program as performing some process for each line in the file.
# or, think of an awk program as a big loop in which you define how to process
# lines of input, one line per loop iteration.

# the simplest awk program has the following structure:
# PATTERN { ACTION }

# ...where PATTERN is a text pattern that is to be matched in each successive
# line of input, and ACTION is the code to execute if the match is successful.

# the simplest possible PATTERN to match is nothing. it matches everything.
# the following valid awk script will print each line that it matches, meaning
# that it will print everything.  whatever file you pipe into it will be printed
# back, line by line.

{ print }

# an easy way to test this script is as follows (minus the greater-than sign):
# > ./01.awk /etc/passwd

# NOTE: see the shbang line? notice the "-f" after the awk filepath?  that needs
# to be there if you're piping a text file into an awk script.  by contrast, see
# script 00.awk which does not take a file as input and does not need the -f