To decompose the example above:
NR > 1 {
print $1, $4
}
So, knowing the above semantics, the meaning of the above example should be clear: If the number of fields for this line is larger than 1, print the first and fourth field of the line. It's a very powerful paradigm, and you can do crazy stuff with Awk. Examples are an x86 assembler [0] and a SASS-style CSS preprocessor [1] (plugging myself there a bit).
Unix coreutils are very powerful once you're familiar with them.
[0]: http://doc.cat-v.org/henry_spencer/amazing_awk_assembler/ [1]: https://github.com/deuill/fawkss
$NR stores the number of records (or the current record number) not the number of fields (that's $NF). In the example the "NR > 1" is meant to exclude the header line from the output.
NR is initialized to 1 on the first line, and is incremented for every subsequent line read. So, in this case, the above pattern will match any line after the first.
That it is present on pretty much every Unix-like system, and most other platforms with a "real" OS, including platforms where finding a modern Javascript implementation is impossible.
It's also a very small language, and the default of parsing records from standard in and splitting them by a field separator and pattern matching on them makes it very well suited for compact filters without extra seremony (some other interpreters have flags to give an awk-like exerience - e.g. Ruby (MRI) - but none are remotely as likely to be installed everywhere unless you go for more cryptic tools like sed).
There's nothing intuitive about programming. A pencil is intuitive. Learning how to program gives us advantages but it requires effort.
The real problem here is that you don't want to learn. You'll be repeating the same mistakes.
> What are the practical applications of knowing AWK over knowing JS?
It's fast, has a small memory footprint, and plays well with unix pipes.
> Besides the shell voodoo
It's not voodoo. It's a useful programming environment for getting work done.
> I just want to understand why learning a completely new set of grammars with a very limited domain would be worth the effort.
It's a specialized language for extracting data from delimited byte-streams. It's not a big language and not a lot of effort is required to benefit from it.
Where the domain is well-understood it's great to have a domain-specific language with short-hand syntax that abstracts away the unimportant details. I don't have to define functions or call any methods. I just get some variables because I know awk just takes a pattern and splits it on a separator... it saves me a bunch of work. Once I understand the language I can manipulate field-delimited byte-streams with little ceremony.
The bonus is that awk plays well with the *nix environment. Anonymous and named pipes, etc are really useful.