1.9 Summary
-  Programs in awkconsist of pattern–action pairs.
-  An action without a pattern always runs.  The default
action for a pattern without one is ‘{ print $0 }’.
-  Use either
‘awk 'program' files’
or
‘awk -f program-file files’
to run awk.
-  You may use the special ‘#!’ header line to create awkprograms that are directly executable.
-  Comments in awkprograms start with ‘#’ and continue to
the end of the same line.
-  Be aware of quoting issues when writing awkprograms as
part of a larger shell script (or MS-Windows batch file).
-  You may use backslash continuation to continue a source line.
Lines are automatically continued after
a comma, open brace, question mark, colon,
‘||’, ‘&&’, do, andelse.