- Awk is defined in POSIX
- Awk is on more systems than Perl
- Awk has more implementations than Perl
- Awk is on more systems than Perl
- Awk has more implementations than Perl
Perl is more regular than Awk for the simple cases and is more usable for anything that isn't merely iterating over input.
Of course, you shouldn't any of awk/perl/shell for tasks that aren't being run by you or are over say 20 lines long.
Asking a new hire to "learn awk" vs "learn perl" have two very different time investments attached to them.
Tasking someone with "learning a subset of perl" begets the question "what subset?", and a very exhausting conversation with someone(s) routinely asking "so?" follows. After spending a large amount of time re-litigating which subsets of perl features we want that awk already supplies.
so?
> Awk is on more systems than Perl
By what metric?
> Awk has more implementations than Perl
so?
Awk is older and as a part of POSIX the version found on unix-like environments will be (outside of extensions) compatible with others. If one or one without the extensions you want isn't present you can choose an implementation, even one in Go and it'll work.
Perl, and I've been writing Perl since Perl4, doesn't have those characteristics. It's a much more powerful language that has changed over the years and it is not always present by default on a unix-like system. Because the maintainers value backward compatibility, even scripts written on Perl5.005 have a fair chance of working on a modern version but it's not assumed (and you shouldn't assume anything about modules). Because Awk is fossilized, you can assume that.
One reason for this is that the popular BusyBox project includes an Awk implementation: BusyBox Awk.
Pretty much everywhere there is BusyBox, there is an Awk, unless someone went out of their way to compile it out of the BuxyBox binary.